i woudl go with 2 new tires instead of just getting 1. once you get one of one kind and one of another it will be hard to get either to wear out at the same time, so you will be constantly changing out one tire then the other. also its just my opnion, but getting matching tires would give me piece of mind in terms of wear and performance. just knowing they were both performing equally would be nice imo.
patching over or in place of a failed patch would just be asking for trouble
hope that helps you out
