Tube preamps, basic design parameters

I am looking to add a tube pre to my HT system. It’s been in the works a while, but time to get serious. Not being technical by nature, I’m finding myself lost in the choices. Asking for advise on what to buy in any given budget results in individual preferences from other uses that I can’t compare to my own preferences. 
My basic thinking on adding a tube pre is to add that nebulous concept of ‘more involving’ to my listening. I don’t feel my system is lacking much, but may be slightly top heavy (more highs than lows?), but only very slightly. My only exposure to a tube component thus far is a PrimaLuna at a dealer, and it did sound wonderful....although no component or the room, obviously, was mine, so how much was the pre amp is anyone’s guess. I do value accuracy and definition, but from my reading, most tube preamps now have moved far away from the old days where you had to choose that over ‘involving’.

Is there a way to predict, based on design philosophy of any given manufacturer, what ‘flavor’ I can expect? LTA has a design they champion in their MicroZOTL line, there are many small outfits with owners/designers of no doubt very creditable knowledge who all claim the best value, bang-for-buck designs, and bigger operations with larger R&D and yes, marketing budgets who make great claims. 
I get it, there is no ‘best’, but is there a way to translate design philosophy into expected sound flavor? Is an 8 tube pre amp by its nature going to produce a different flavor than a 2 or 4 tube one? Is a separate Power Supply a deal breaker? Those kinds of things? I will say I’m not particularly interested in buying something I will need to send back for upgrades every year (another thing I read about in some manufacturers, being able to order the build almost a la carte, as if I have a clue what I’d want the build to be, when I’m still green as grass).