adjusting valve lash 422 SB

3402,
You are close to the 290 @ 050 limit, so use the 8 position method. Some people are making too much of this, almost anal.
You have roller lifters.......& presumably roller rockers. A roller lifter has two areas that can vary in dimension [ that a FT lifter does not ]. How accurate the hole is in the centre of the roller & how accurate the bushing [ or needle rollers ] is machined; this can change the lash. Same deal with the roller on the rocker. Then you have base circle run out. You could adjust lash when these variations are ALL at a low point. Then after rotating the engine, you check again.....& your lash has tightened 0.003" because the high points have lined up. You have a WTF moment.....
There is no way of knowing if you are on the high or low side; does not matter which method you use. Also, with the lifter, any error or tolerance gets multiplied by the rocker ratio...
That is why it is best to use the simplest method for initial start up....ball park number.....& then use the random method for the most accurate lash adjustment.