PFR sizing for 6 max tables...

With a 20% VPIP, should you vary your raising size depending on position...
Is it important to raise more from early position with good hands to protect them, or should you raise less because you will be out of position for the hand...
Similarly, should you raise more in position knowing you will be at an advantage the rest of the hand...
I am familiar with the concept of effective stacks and stack to pot ratios... conversely should you standardize your preflop raises and keep your preflop raises consistent no matter position.
Just looking for opinions...

Keeping your raises consistent is going to be your best bet. I'm just assuming that you're at the micros, and your raise sizing won't matter much down there. The difference between 2.5 and 4BB's really isn't that much to someone who has a VPIP of 40+.

Also, you say your VPIP is 20, but that really doesn't mean anything positionally. What are your positional VPIP stats? They should be the lowest from the earlier positions and highest at the later positions. If they are all pretty much the same or they are scattered, then you are more than likely playing your cards and not your position(given a decent sample size).

Occasionally, if I have extremely loose tables, I will vary up my PFR sizes with premium hands from EP, betting 1-3BB's more than normal because I know that I will be getting the call from at least 1 of them, but enough to get a couple to fold, because it's never fun to go to the flop with QQ+ multiway with 5 others. So really, it's more situational than standardized.

I generally make my raise size the same except from the BTN I usually make it smaller there. You are opening a wide range so generally your hand will be weaker plus you are risking less money to steal the blinds. I usually make it like 2.5bb's from the button. I might raise more with premium hands if I know that know one at the table is paying attention to raise sizes.