Assuming that 3 pts per IP also means 1 pt per 0.1 IP, here's your breakdown:

Top 250 Hitters Avg - 439 points

Top 250 Pitchers Avg - 282 points

Try adding (AB-H) = -0.5 pt. Doing that gives you the following averages:

Top 250 Hitters Avg - 266 points

Top 250 Pitchers Avg - 282 points

That's not quite perfect, and people will still argue about relational values of the events, but it should give you a good starting point from which to begin tweaking.

Important Note: This is a generic comparison assuming you start the same number of pitchers as hitters in a 12-16 team league. If one of those does not apply to your league, this comparison will not be useful.