FET cooling BoSoZ

BoSoZ (unbalanced only):

I use 21K/W to220-style heatsinks for linestage and psu fets. The Digikey heatsinks in the Nelson Pass part list does 15,6K/W.

Are mine too small and should I replace them? (my amp is not tested yet, so I don't know how warm they get) ?

Is it not true that the two fets in the psu gets more warm that than the ones in the line stage (my psu has same specs as the one in the article) ?

I also made a "grilled" topplate with holes.