One turntable with two arms, or two turntables with one each - which would you prefer?

I have 3 turntables mounted in slate plinths, using Pennsylvania black slate. (I assume not all slate from all sources is created equal.)  The quarry in PA that sold me the slabs also was able to hone both sides of each slab perfectly flat and champfer the edges. Then in York, PA, I found a waterjet company that "learned" to cut my 3 slate slabs so to fit respectively, my Denon DP80 (50mm thick), my Lenco with PTP top plate (50mm thick), and my SP10 Mk3 (75mm thick).  In the case of the Mk3, the slate alone weighs about 75lbs, after cutting out the hole for the chassis.  I had a subplinth made out of solid cherrywood, for the Mk3 only, and bolted that to the bottom side of the slate slab.  I tell myself I can hear a tick better performance due to combining slate with cherrywood. This all sounds very good to me, but once having made the effort, I would not do it again.  Nor do I fret about whether or not Panzerholz or some other material might sound better.  Suffice to say I think all these materials are excellent choices.  Slate is just the road I went down.  I also agree, granite not a good choice; I don't really know what it is about the internal structure of granite that makes it less suitable than these other materials.

maybe @dullgrin would like to make a further follow up contribution to confirm if the information offered since his last contribution, is satisfactory to help with the initial inquiry made.  

" Nor do I fret about whether or not Panzerholz or some other material might sound better. "

The journey for myself through HiFi Encounters and building a HiFi System, is based on growing in experiences through being demonstrated different options that can be incorporated into an owned system.

I don't see myself as a lone entity in this understanding of a Journey with HiFi as the interest.

There is for me, a pursuit of knowledge, especially about how one is stimulated by the use of certain components or an assembly of certain components.

As one's experiences grow, they are quick to identify where a stimulus is present that is an attractor or a repellent.

As one's experiences grow, the likelihood is that there is a much more selective mind set in place, and a willingness to change prevails, the stimulus encountered can prove to be very persuasive. To the point an outright rejection of an idea or immersion into an idea takes precedent.  

I am not one who is to Stagnate and be found Resting on One's Laurels, and especially not one who will Show Contempt Prior to Investigation.

There are tremendous discoveries to be made, when a mind is open to what others are doing, where differences are obvious to one's own choices.

It is with the open approach and willingness to learn that new discoveries have been very persuasive, bringing change, hence I was introduced to Plinths produced that were very different to my 'one time favoured' Mass Material Plinth Design. With the result being the Mass Material Design are no longer favoured and wanted to be used as the regular method.

@lewm With respect to granite, presumably the crystalline nature of rocks can affect their ability to resonate? All I know about them is to do with their abrasive qualities when lapped and used for honing straight razors. And now I shall be accused of going off topic again, so...

My plans for tonearm pods are underway. They will be made of brass rather than stainless steel, and black ceramic coated just for visual matching purposes. SME mounting plates on top, and three spikes underneath. The mounting plate will be precisely 90mm above the tips of the spikes, which is the same as the built in arm plates on the Model 10 tables. My next choice will not please everyone: I shall place a pair of SME M2-9 tonearms on them. These are pretty much like the 3009, but straight instead of curved, using 309 type headshells instead of the 3009 type, and have a damping trough. I have half a dozen 309-style headshells being one reason, and trust in the wisdom of Alastair Robertson-Aikman is another. It will probably be a couple of months for the machinist to finish the pods, so I'll have to be patient in the interim.

Thanks for the interesting conversation, everyone. I've been reading with interest all the responses.

This thread, for me, was not so much a 'tell me what to do' or 'help me make a decision' type thread, more conversation starter, born of a genuine interest in how others approach their desired analog playback chain. I don't think there's any universal 'right' answer - just what works for each of us. It's interesting to see the responses.

I will say that my interest in the topic arose as I started to think about a second, all analog system. I've had a turntable in my system for at least 20 years, now, about as long as I've been in the audio hobby.

Over the last couple of weeks, I've assembled that second system - with the assistance of some great dealers and distributors. They're out there. Shout out to the teams at Kevalin Audio, Next Level HiFi, Bluebird and Nashville HiFi (no affiliation, just a happy customer - they all have been fantastic to work with and I think they're worth knowing about).

For now I've landed on one turntable and tonearm in my main system, and one in my second system. Neither of my current tables really has an option for a second tonearm, so I will look to add another table - maybe with two tonearms, maybe not - to the second system once my checkbook has recovered (!!!!). Adding a dedicated option for a mono cartridge in the second system is my next goal.

In any case, thanks for the responses all. Keep 'em coming. And happy spinning.

@dullgrin Thank You for a very fair assessment and your encouragement.