If possible, drill the hole in a way that the bolt can't back out at all when the safety wire is on/tight, based on what you're tying it to, which may be the other bolt.
If the cap is a bit hollow/shallow, straight through works. If not, you can go straight through the whole solid cap, or through at an angle, which can be hard without breaking (all of) your drill bits.
At South this weekend we heard some rumblings about some big controversy with Moto-D. People are saying don't buy from them but I never heard the reasons why. Does anyone have any info about all the hoopla that's going on?