How tight to set solid lifters

Consider this. You are using one of the above adjustment methods, 4 pos, 8 pos, etc to set lash.....
For each method, you are measuring the lash on the same point of the base circle, which will have some run out.....You could be on the high point, the low point or in the middle.....
If you are using a SFT cam, along with stock rocker arms, then you will have the least variation of lash.
Now add roller rockers. You have a roller tip that might not be centered; rockers might run on needle brgs that have wear/play. The higher the rocker ratio, the greater the variation.

Roller cam now. Wheel on the roller lifter might have the hole not quite dead centre. Or wheel is slightly out of round.
The ball ends of the pushrods look perfectly round to the naked eye. But are they? If there is a 0.002" flat spot, which you won't see, & that is where the ball makes contact with the rocker, you gain 0.003" of lash with a 1.5 rocker. Next time around, the prod moves & contact is made elsewhere on the tip...& lash is less.

All of the above variances can show up in 'WTF, the lash has changed?'

I use the 4 position method for initial lash setting. It is veeeery accurate for 95% of cams being used.
After that, I use the random method which is the most accurate.