Does anyone know the best way to knock off SIM's at these levels?

hit them early with $$. You have to do it quick or they will bleed you dry. CVs are easiest, but recruit might not accept them...so scouting trips are a good option as they cannot refuse those and you still get your $$ in play.

Usually how many CV's does it take for each level?

For D1 it usually takes 9-12 CVs if you're at a major conference school (non-elite) and done in the first 2-3 cycles.
For D3 it usually takes 1-3 CVs and done in first 2-3 cycles.

I only have teams in D1 and D3 currently and can't really remember guidelines for D1AA and D2 but obviously somewhere in between.

In my experience positions like TE, K and P have taken less CVs than listed above.

At D2 it takes about 4 or so. Then again I think your prestige and school history come into play. I am at a top tier school in Camp and I can sometimes get them to turn green for me with 2 cv and a hc scout trip. I could totally be wrong as better coaches then I could weigh in on if prestige helps lower the number.

CV = coaching (head coach or assistant) visit or Campus Visit?

Everyone uses CV and I just want to make sure

Campus Visit

That would explain why it takes me so long to knock off sims....