I still don't see where the OP said what he was actually doing with these boolits. On the weight question, +/- .3 grains may not even be noticeable if the target is close enough.
The real problem is he started with crappy boolits and probably won't get any good data from them, just a bunch of shotgun groups and a trip back to the loading bench.
If I was handing out advice, I'd say to get some recommendations from other members about good quality commercial cast or ask to borrow some well-made boolits from somebody (Sorry, I don't have any cast in that size), then he can get down to some serious load development and accuracy testing.