I guess the approach we take with players of 120+ games experience is, that most of them have set their scoring levels and patterns. Unless their is evidence to the contrary, we just have faith that they will score at or around that level. Looking at your 3 candidates:
Jack K, 144 games, ave this year 99.8, price $543,200, previous seasons 109, 112, 81, 100 - level 109
Priddis, 157 games, ave this year 100.2, price $496,900, previous seasons 101, 110, 114, 109 - level 109
Mundy, 192 games, ave this year 99.7, price $491,600, previous seasons 104, 89, 107, 94 - level 105
So if you believe/are happy with the level I have set for them, they should score at for the remainder of the season:
Jack 112, Priddis 112, Mundy 107
Looking at their respective draws, games left against the top 3, 4th - 8th, 9th - 13th, 14th - 18th:
Jack K - 5, 2, 5, 4. - FTB tough to easy -20%, +27% - Draw factor 100.5%
Priddis - 1, 7, 5, 3. - FTB tough to easy -5%, +8% - Draw factor 101.2%
Mundy - 5, 2, 3, 6. - FTB tough to easy -6%, +12% - Draw factor 102.6%
So all Things considered, it looks like Priddis. The near $50k Price difference over Jack pushes him to the front. Though my gut tells me Jack might outscore him, I'm not sure it is worth the extra $50k.
I'll do a full table on Mayne for you in this weeks Trade Tables thread.
Good luck
EDIT - I'm not sure I agree with your assessment on Bomber. Everything I've read says he wouldn't let his kids win a game of tiddly-winks unless they earnt it, he is so competitive. I can't see him just holding PJ's spot, and not trying to win a flag.