Hmm 750 is Kind of small for medium rats... I was worry to give last night 135g to my 1110g female so I totally Understand your concern...

And with 6 snakes...

Talk to Guy/Gal from your pet store if He/She will be able to buy off excess feeders from you and if yes... start breed.. with one pair of rat breeding and some small from show you'll be able to find a balance... and if you have F/T eaters or Fresh killed eaters maybe you even will not need to sell of excess feeder just feel up Your Freezer...