Before you start modifying you may want to consider these options:
spark device in pistol shape spark deviceUnfortunately I do not know the proper English terms for those devices (sorry but Iīm not a native speaker). Maybe the links provide a little help anyway.
BTW: Galvanized threads tend to have rounded tips on the threads. That would not work too well (BTDT). You may need to recut the thread for sharp tips. In our hardware stores they sell the flints without holder. Before I used PVC pipes I used a holder in the style they use for sets of Allen wrenches on rings (
Allen wrench). That kind of holder is easy to make from work hardened wire.
I have no affiliation with the linked companies.