I personally, if you can afford it, would consider getting a level 6 or level 7 trainer with high salary that you buy for really cheap, and use him to train up the inside skills. You could get 3 pops in ID, 1 pop in IS, and 2 pops in Rebounding and he would be a freak. More ID would be great as well. Then you can revert back to a lower level trainer and it won't have cost you much.
Just a different perspective :)