Building an F5 Turbo v2 (in-Progress)

F5 Turbo V2 TH1 and TH2 with or without?

hi guys this is the first time I draw this PCB I have a question the TH1 and TH2 they go on the Q3 and Q5 do they need glue or just thermal compound or does not need any at all? oh note the power semiconductors are there only for illustration purpose
 

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So after letting my partial V2 build set for a couple of years I'm back to getting it going. let me describe mine it is part V2 and V3 together. I'm using the cascode setup but not using the output diodes. I'm running ~35 volt rails. I have 2 output transistors per half for 4 total per/channel. I'm testing currently now on bench at 1.5 amp per transistor bias. the heatsinks have settled at 55c deg after 2hrs. Amp is stable w/ 2-4mv offset. It is always a question as to what level of bias you should use. It gets confusing bc people will discuss and you do not know whether they are talking about bias per single transistor or combined with two transistor. I'm assuming single transistor. One thing that is peculiar is that my PS was completely balanced during load test with resistor load but powering amp one side is a volt lower than other side. This might be bc I'm using IRFP250 and IRFP9240?? The bias is all the same though through each half no mismatch. Anyone have any idea on this? Does it matter? maybe asymmetrical clipping??