Tubes or stick with S/S

Note that Dennis Had's amps are almost unobtainium and I found mine, a late 2016 sep ("p" for pentode), simply from a lucky Ebay score. You can buy the mono blocks from Moon Audio but they're pricey although likely worth it. My little Firebottle version is 12wpc or something (depending on the tubes you stick in it) and drives Klipsch Herersy IIIs with gusto. A Steampunk tone monster that has astonished me from day one. I'm also a mechanical watch freak...latest faves are an Oris Divers '65 with the distorted deco-ish numbers, and a Ball Trainmaster Power Reserve (tritium glow tubes...who doesn't like those?)...another hobby that exactly zero of my friends care about. 

"Note that Dennis Had's amps are almost unobtainium"

See the link posted above. Brand new 300B FireBottle SET for $2K, plus shipping. Looks like a nice piece. Audio Nirvana also has a 300B SET for $1595. Haven't heard either.

I follow Had's stuff on Ebay as one of my "saved sellers" (in fact the only one of those), and if I actually felt the need for another Had amp I'd buy that 300B version immediately (I wonder why his amps don't sell in the first hour of listing 'em)...still, "almost" unobtanium  seems accurate when a very well regarded amp designer manages a couple of dozen Ebay only amps a year, likely because of commitments to build the Inspire headphone amp for Moon as well as the previously mentioned mono amps...by the way the mono amps are 25 watts each and at 4 grand a pair seem to represent a serious bargain in this Kondo Ongaku $95,000 world. Buy a Had amp pair and save over 90,000 bucks...money to bribe the kid into college, get that Porsche Cayman, buy your own massage parlor...endless possibilities...

I switched in January this year from refurbished Dyneco monoblocks to a Primaluna Dialogue HP powering Tekton speakers with 95 or so db sensitivity.  The PL is really some amp, loving it.  However I want to add that although I'm not familiar with your Cornwalls from this thread it seems they are efficient and some advice was that you can go with a lower powered tube integrated.  I have my system ina fairly large room with a high vaulted ceiling and I sometimes like to listen loud.  Upscale thought I'd be fine with a regular Dialogue at 36 watts but my Dynecos were 60 and barely doingbit so went with the HP at 72 watts and I've used every watt.  I've had it turned up almost to full a few times, depending on the volume of the source recording. If you like to occasionally recreate a live rock concert at home then don't be shy about watts.

Manley Mahi Mahi monoblocks.  Beautiful sounding, quick as hell with great imaging and natural timbre.  Vocals and acoustic instruments sing.  Can be found for about 2K used.