Before you mix and match R2R with a THX, read a few posts from here: Is THX (precisely: is AAA) a bad thing?
I will not the same forum members that seem to enjoy R-2R DACs don’t tend to use them or have the highest opinion of THX amps. Just sharing my 2 cents and I’m NOT saying something is better than another, but larger point I have to share which is your source chains matter and synergy is VERY important. I think Zeos thinks so highly of the THX amps because he doesn’t really mess with them in terms of DACs and his gear plays to the amp’s strengths.