Actually, the size constraint is on the size of the compiled P-Code, which means you should probably watch for different things. Things that don't compile down to P-Code tokens (e.g. string constants, embedded SQL) should be reviewed carefully. If you have a lot of embedded SQL (a common trap for those new to PB), you might want to consider encapsulating that in a DataWindow, which will be more network-traffic-efficient at run time anyway.
Good luck.