Cast bullets can be expected to not expand to any appreciable degree, but that's ok, because they will make up for it with a big wide meplat if you use a Keith style bullet, a lyman 429421 for example, or other semi-wadcutter. A sound investment would be a lyman reloading manual, lots of cast bullet information and loads, or a lyman cast bullet hand book, even more information and loads. I guess my answer would be that you don't have to sacrifice anything, except expense, to use lead bullets. You may just have to approach it a little differently.
Sounds like you've got a good one, congratulations! Don't forget that Valentines Day is this week, otherwise somebody might try and take that one away from you! :eek: