How about this:

1 point per one point of batting average.

10 points per RBI

25 points per HR

I figured that based on about 100 ABs, 100 points in batting average was 10 more hits, so I figured 10 more RBIs should be worth about the same, so it's really sort of kind of maybe 1 point per hit when you get to the end of the month and 10 points per RBI.

I figured homers were the hardest to get, so they should be worth the most.

I'm not necessarily saying that this is what we should do, BTW -- just throwing some numbers out there.

So based on the above, this month would be as follows:
Code:
PL     12  25  .456  or  300 + 250 + 456 = 1006  
DJ     11  39  .365  or  275 + 390 + 365 = 1030 
DM     11  33  .400  or  275 + 330 + 400 = 1005 
JG      8  15  .271  or  200 + 150 + 271 =  621

"Difficult....not impossible"