Oh dear..! That's a shame, after all that hard effort. It's all experience, of course, but still...
I'm not an expert in these matters (far from it..!), but I would recommend, if you want to change the bridge, forking out the £70-100 for a bought one, and modifying it to suit. A second-hand one would be even better, from a cost point of view. If you're really set on a DIY version (good on yer..!), try to find a suitable piece of close-grained maple as a blank. It has to be a hard wood (maple is hard, usually...), but also with close fibres, for the reasons illustrated by the break you've now got. It's not an easy task, especially with only modest hand tools; it's not for nothing that these things cost so much..!
Good luck, in any case, and thanks for the updates, they're very interesting and instructive.