If the pin system would be adequate to hold what he normally makes they should be able to hold a kilt pin. In general there shouldn't be more stress on a kilt pin then in other applications. The one thought I have is the use of a pin "lock." Many people use a rubber band as a back up to the pin. With the clutch pins pass the pins trough the apron of the kilt, through a piece of rubber band and then put the clutch in place. Even if the clutch is lost the rubber band will hold the pin in place.

The same thing is done for the safety pin style pin. Pass the top of the pin through the apron, then through a piece of rubber band back through the rubber band, out through the kilt at the bottom and close the clasp.

Remember that the kilt pin goes only through the top apron. Do not pin the two aprons together. It is the weight of the kilt pin that does the work of keeping the apron from blowing, beyond that it is blink.