Number of Bacteria per plate?

[TJ]

I was wondering if someone has experience with trying to maximize 
the number of bacteria plated per LB agar or similar plate. I am trying 
to electroporate a library into E coli and plate out the resistant 
bacteria to prevent mutant overgrowth.  

I am wondering how many seperate clones can selected and grow per plate.   
For example, I  think in the past I electroporated a ligation and was 
able to see appoximately 10^6 individual Amp and Cm resistant colonies 
on a 15cm^2 plate.

Any help, thoretical or practical would be appreciated.

thanks
tj

T. J. Cradick
UCSF Immunology