Slots per mod

I wanted to know if there is a way to figure out how many 'slots' a mod consumes on the MCForge system now. I know used to it was per item in the .jar file, but I don't know how far into compartmentalization the new API code has put the items into..

Reason I ask is because I was getting slot errors when combining this mod with BC and BTW, (with MoreID Logic gates as well, but I doubt that takes more than a couple of slots). I did not bother with changing the Slot ID's, because the items in question conflicting are midway thru the list of content added, thus assuming I had used up most of my space in my .jar anyway...

Any suggestions?

Thanks, but I also want to account for the TOTAL space that I'm using in my .jar so far... because if I have more room to fit more mods in, then by god I so want to...

Edit: How do I create a custom config. file to maneually force blockID's for mods? I'm finding that the best solution would be to get a raw figure of each block past the base MC and just stack each and every new mod block in a file that way... (tedious, I know, but it seems like a better solution for this problem atm...)