I want / need that tube goodness in my sound but must also have that SS grip, bass control, transparency and image precision.
The Lamm IMO/IME has a classic solid state sound in that its bright and has a touch of solid state harshness. If your speakers are bright (I've not heard them) then I would expect the combo to drive me out of the room. I've not owned the Lamm but a friend of mine in town had them so I've heard them many times.
The Focal website isn't all that great so its a bit tricky sorting out the speaker, but it appears that while they claim '8 ohms' the woofer array is actually 4 ohms. This type of speaker isn't friendly to tube amplifiers! To run a tube amp you would need to use the 4 ohm tap which puts the amp at a disadvantage. So you're going to have to find something solid state. I get why you want that tube input stage of the Lamm- maybe that would tone things down a bit....
But here's what is going on. The Lamm, like most solid state amps, uses feedback, but in insufficient amount so the distortion generated by the feedback itself causes the amp to sound bight and harsh. You need an amp that can behave as a voltage source though, so IMO you'll need an amp with a lot more feedback, enough so that the amp can clean up the distortion caused by its feedback. This value tends to be north of 35dB (or maybe 40dB). That's a lot of feedback and there are not that many traditional solid state designs where that's going on. But two are the Benchmark and the Soulution (the latter of which you've expressed a dislike). But if you want to know why these amps will sound smoother than the Lamm its because they have so much more feedback. Quite literally, they are sounding more 'tube like' because they are lower distortion. (And in particular the higher ordered harmonics; the ear is keenly sensitive to these because it uses them to sense sound pressure, and the ear has a range over 120dB! The ear assigns a tonality to all forms of distortion; the higher orders are heard as 'brightness' and 'harshness' despite the frequency response being perfectly flat.)
Your other option is to find a class D amp that you like. Class D amps usually have a very low output impedance so will drive this speaker well. There are very big sonic differences between class D amps, so just because you've heard one does not mean you've heard them all. The differences between them are as profound as they are for any other kind of amp, like tube amps or transistor amps. But the things that cause distortion in class D amps tend to result in lower ordered harmonic distortion rather than higher ordered (as in traditional solid state) so what you're looking for is one that sounds smooth but has the impact you're looking for in the bass at the same time. They do exist.
