Not having built a Triwatt, my general suggestions would be to download the current schematic and layout, the layout is your friend. With regards to the bias reading, make sure that you have the bias switch (for 6V6 and KT66) power tubes in the correct position. I have been reading the Triwatt forum back to front (considering it for my next build) and several experienced builders had problems with setting bias only to realize the bias switch was set in the wrong position for the installed power tubes or wired incorrectly. Also mentioned, lot of people missed jumper connections and the usual bad solder connections (been there, done that). Someone else with more experience will, I hope, address your specific questions. Best of luck
, I see from other posts that it is an awesome amp
PS Welcome back