I think you have to recruit a QB and RB every year. I would take every good DT we can get. Why? Because some can be moved to the OL ala Jason Pinkston and John Malecki, among others. (I include in DTs large DEs who might grow into DTs.) We clearly need TEs, so I would sign 2.
Including converted DL, we need 3 or 4 OL, 2 LBs and 3 DBs. 1 or 2 WRs should be enough.
The thing is though, while you have to recruit to fill needs, you can’t not take a special player no matter what the position is. So, my breakdown would be:
QB, RB, TE (2), OL (3), WR (1), DE (2), DT (3), LB (2), DB (3), Special Talents (2, more if you can). That’s 20 which I think will be the size of the class.