[sansterre]

In theory (and I hope to do this when I get home now) you could:

Create a base ML league
Turn injuries, fatigue, player development and suspensions off
Figure out how to control your team so that no roster moves get made

Save it as a template

Now Edit the Catcher Ability on all of your team's catchers to max (whatever that is in your league; in 1-10 leagues it's 190ish).
Sim a season. Record the Ks and BBs for your team.

Reload the template. Edit the Catcher Ability of your catchers to the minimum (10 in a 1-10 league).
Sim a season. Record the Ks and BBs for your team.

Repeat as many times as you think you need for a bigger sample size.

Note the difference between the top CA stats and the bottom CA stats.

One point in CA for your league is worth:

((Max CA Ks / Max CA IPs - Min CA Ks / Min CA IPs) * 2 + (Max CA BBs / Max CA IPs - Min CA BBs / Min CA IPs) * -3) / 9 / (Top Rating in your scouting system - Bottom Rating in your scouting system) * Projected IP Fielding at Catcher (I usually estimate 1000)

Or so the theory goes.