I guess you are thinking to do as much as you can to toast the IS score of the bigs in favor of upping their JS some, and in addition to that adding JR. The problem is they wont shoot that much from outside and you can not eliminate inside shots from the game. In testing you can try to figure it out. They will still take some inside shots. Putbacks etc....
Production wise its good to have some ability to convert those shots...how much they can get out of a high JS and JR without high DR/HA/PA is debatable...and are you gonna put OD on them or not? If/when you get those stats high enough the player switches off to SF or guard builds.
The high DR/HA/PA is also especially important for the low IS build specifically because of the putbacks. One of my trainees right now is "up" to 6 IS through secondary training only and is playing a lot of C and PF this season to try to improve ID and RB. He's a decent enough shooter for outside (10/8 JS and JR) but he's also got 13 DR and 10PA at the moment. He's taken very few actual inside shots - the stats aren't up to date but he had at one point 7 total inside shots attempted, 29 drives, 31 jump shots and 19 threes. Since he has 22 offensive boards in that stat set, if there wasn't the higher ball skills he would have just dumped up a lot of sure-fire misses from inside - instead, he kicks it back out for the traditional 24-second burning of the shot clock that is one of the hallmarks of the Princeton. ;)