I've similarly found that most Campy seat post pinch bolts broke at the base of the threaded (male) end. The socket for the male side's allen wrench is pretty deep, and thus doesn't leave a lot of metal under the base of the threads. So, too much stress breaks the bolt.
The Sugino seat post bolts have a more shallow socket for the allen wrench. The male side requires more care when engaging the allen wrench, but I've never broken a Sugino bolt, ever.
The ridges (splines?) on the female side are notably more coarse on a Gipiemme bolt compared to Campagnolo. A used frame I bought years ago had a Gipiemme bolt installed in the seat lug. The female side had not fully seated due to the coarser splines. I had to drive out the Gipiemme bolt by unscrewing the male side pretty high (but still engaged in the threads), and then pound on the right side's bolt head with a hammer. After about 10 minutes of vigorous pounding, the left (female) side loosened up and came out.
A Campy 19mm bolt then went in quite easily, and seated fully.
I agree: The mixed bolt solution is probably the best option.