I have not heard the Lamm amps in direct comparison with the Belles, but I would expect the Lamm amps to sound better...they ought to at more than three times the price. Please note I was referring to the Lamm hybrid design, and not the Lamm SET amps.
The 150A Reference amp and 350A Reference amp run cool. I have owned each, but I have only owned a single 350A Reference whereas I own 150A Reference monos.
I have been told that the Belles amps are meant to be left on, but I turn mine off each night. Energy consumption guilt. A couple hours of warm up gets them up to optimal sound, IMO.
Do they texture like tubes? That's a tough question. No solid state amps that I have heard sound like tube amps, but they do some things better than tube amps I have owned. The strength of the Belles amps is their tonal balance, sweet top end, bass control, and resolution.
The VAC tube amps I have owned were stunningly clear and holographic. However, they were not as tonally balanced and their bass, while excellent, was not as deep and solid. I also would not characterize them as warm because their top end has so much sparkle.
The designer of my Silverline speakers recommended Belles (or Pass Labs) amplification, and he was correct IMO. Have you asked Israel Blum what amps he would recommend for your Coincident speakers?