It would have to be more than 33%, because they won't take exclusively 3 point shots. They'll be some long two's, some attempts at the rim, etc. So if it's 33% from 3 and 50% from 2, it'd be even. But since jump shooting teams are typically (I think) in the lower 40's for average FG%, the percentage from 3 would have to be higher.
A few seasons ago (probably like 5 or 6) I saw that Poland's NT had a PF that was shooting a couple 3's a game in league play, and hitting them in the high 30's percentage wise. That's sort of what got me thinking about this.
For the longest time, I don't think Silverbacks had a big that was over 60-70k in salary, and most of his bigs were half that. They were all specialists with only rebounding, some ID, no IS or SB. So he put his payroll towards much more expensive guards than normal.
If through training bigs, we can save on salary, and toss out some NT caliber guards...might the overall 3pt and 2pt FG% be good enough?