Review Technics SB-G90 floorstanding speaker 

''So you have been able to read that this Technics is a big heavy, 3-way bass reflex speaker. So far so good. The nominal impedance is 4 Ohms and the continuous load 100 watts. 200 watts peak. That’s more than enough for many a living room. It takes about 40 watts to get it going. We estimate that a tube won’t go very well, but who knows with a heavier 300B it might work, considering the efficiency is still about 88 dB. That’s not super high, but it’s not low either.'' see review here

Mike

Based on my experience trying to match 86dB speakers with a tube amp, the size of the woofer and controlling that driver have a lot to do with whether a tube amp or SS will work better. The JBL woofers are not that large. If you can demo them, do so. But as you have not purchased the speakers, and if you can't demo them with your amp, I'd look for better synergy on paper.

I ended up with SS. You can see my set up in my profile.

As for power, in a semi-contained listing area that opens to a much larger open plan living space, I'm generally using 10 watts or less p/c and filling the space nicely. Volume range -40dB to -30dB albeit with virtually unlimited headroom.

I have a pair of Vandersteen VLR-CT bookshelf speakers which are 86dB, my least sensitive, in a 2.1 system. I have used both a Yamaha A S-2200 (90W AB) and a Peachtree Carina GaN amplifier (200W GaNFet Class D). Both perform well with these speakers. I would suggest you use  a moderately high powered SS amp 

I have Janszen speakers 86db at 6 ohms. I use a single LTA ZOTL40 to great effect. The current this amp outputs has more than enough power to make these speakers sing. You could of course use two of them as mono blocks.

You have a nice system. The decision will be made by room size. A larger room will take more power for the same experience as a small room. I run 30wpc from EL 34s into 89db sensitive speakers. I am using the system in a 12 ftx15 ft area. I'm only 10ft from the speakers. There is windows with cutains in back of where I listen and a 25ft ceiling. The is open space leading to a dining room on one side. This is not an ideal space, but it's still sounds great. The room is very important, distance from the system and how far the sound needs to travel with impact realism of the experience. Sometimes experimentation, moving things around will greatly improve the sound.