Depend on the strength of the pocket pair doesn't it? Call 2% of the smallest stack (yours or theirs) for 22, 3% for 33 etc. up to about 8-10% for 99-JJ. Of course you need to modify this for position and the players at you tables.
I have no idea how you came up with this? But the above is full of wrong.
Once we make the decision to set mine preflop, then set mining is set mining. Doesn't matter if we have 22, 55, or even QQ. If you firmly believe that V's range is AA/KK and decide to "set mine" then you need to hit your set and a set is a set is a set...
The biggest factors in whether we should set mine are:
#1) Range we assign villain
#2) Villain's post flop tendencies
#3) Villain's post flop aggression
#4) Effective stacks (ours and villains, we need to be getting 15:1 to 20:1 implied odds)
The greater V"s range tends towards AA/KK/AK, the greater V's tendency to overbet and overvalue TPTK and/or overpairs, then the more profitable set mining becomes
Mathematically we need a minimum of 8:1 odds to set mine since we will hit a set roughly 12% of the time. However, as a community the thinking has shifted required odds to 11:1 to 15:1 to 20:1 over the years because it takes into account the times we hit our set and DON'T get paid off.
As far as position goes, obviously set mining in position is better than being out of position, however set mining works from any position as long as you are somewhat confident you won't get 3-bet out of a pot pre. For the most part, you will be able to limp/call to set mine provided you are 100bb+ deep.
Lastly, ideal set mining conditions are multi-way pots in which you are getting great direct odds to call on top of implied odds (eff stacks behind) and your villains are aggro post flop and will stack off with TPGK+ type
hands. So you hit your set, they pay you off.
Non-ideal set mining conditions are when pots are NOT multi-way and you are up against a villain who raises with a wide range and has a good post flop game and isn't going to overvalue his hands or make incorrect aggro spewtarded overbets... Basically, against these types of villains, you hit your set, they don't pay you off enough to overcome all the times you miss your set and have to fold.