MKB, the F12-X200 is very harsh, tried it. I own a couple of 12LTAs, what was your experience?
I found the F12-X200 is good in most cases with a Kemper and Kone turned off. But in some cases it can sound harsh. I eventually liked it a lot but have lost a bit of enthusiasm lately.
I previously used 12LTA's with Line 6 gear, installed in a Peavey transtube Bandit with the HD500 into the Bandit's power amp in. This was not an ideal tone, but it worked well and held up under loud stage volumes without getting harsh (like most tweeter equipped FRFR's did, including the F12-X200 in some cases).
Since the 12LTA was similar to the Kone, but not exact, I did some experimenting using it in place of the Kone (no Kone yet). I'll say the 12LTA with Kone enabled was much better with the Kemper than 12LTA without Kone on, but the 12LTA had a heavy mid coloration it layered over all the imprints. I would suggest you try the 12LTA with Kone enabled, you might like it.
Over this weekend I should have my Kone and can make some direct comparisons between the Kone, the 12LTA, and a few drivers represented by the imprints (Vintage 30, G12M Greenback). Probably won't be able to record them though until I get a bit more time in with the Kone.