Amplifier recommendations for 86 dB Sensitivity Speakers

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.

I'm running a system at the moment in a 13' by 16' room, with Dynaudio Heritage Specials (4 ohm, 85dB/1watt) and a Conrad Johnson Classic 62 SE power amp. I don't listen louder than 80-85 dB peaks as a rule, hoping for long term hearing preservation and all that. So in essence I'm using that first watt to good advantage, with the other 60-70 watts as headroom. This room has a door, and it can be closed to shut out flow to the rest of the house. It's a sublime combo, and exceeds the systems that I've run in this room over the last few years. I can't support the ideas that tube amps are automatically going to fall short in a case like the OP presents to us. 

I've tried the CJ tube amp downstairs with the 2ceSigs as well, and it's more than fine. The presentation is great and that room is a little larger at 14' x 18'  with significant connecting doors and openings to other rooms in the rest of the downstairs. Here I do prefer the 200 plus wpc into 4 ohms of the available solid state amps. 

Sensitivity is usually specified as SPL at 2.83 volts.  I guess to be precise it is at 2*sqrt(2) = sqrt(8).  From ohms law (etc.) (V^2)/R yields 1 watt into 8 ohms, 2 watts into 4 ohms.

If you get 86 dB at 2 watts, then 4 watts => 89dB, 8 watts=> 92 dB, 16 watts => 95dB, 32 watts => 98 dB, 64 watts=>101dB.

101db=> deafness.  Indeed prolonged exposure at or above 85dB is dangerous.

IMHO 70 watts is ample for your proposed speakers.  The most I have had in my current system is the 50 watts from a Pass Labs XA25 into my 87 dB spec Rockport Atrias, good solid state DOES double into 4 ohms as transistors are current sources.

Currently I have single ended 2A3s (perhaps 4 watts) driving those speakers, exquisitely!  My room is about 20x40, I listen at something over 12 ft. from the speakers.

It might depend on your chosen music genres.  Slam, impact, crushing crescendos are not relevant to my listening, I value timbre, clarity, details - the shape of the notes, and emotional content.