roknhs,
I also mounted a gasser in my super stearman. Though mine is a 41cc. I mounted my charge jack and switch on the side of the fuse
just behind the firewall. As you stated, adding extensions or cutting out factory units and replaceing with new, was something I
didn't want to do.
I would suggest you do not mount anything on the fiberglass cowl. You will find it necassary to remove the cowl on a regular basis.
The more stuff you have to disconnect and reconnect means more chances for error. Also the fiber glass cracks, splits, and peels
more easily at cuts and holes. So the fewer of those, the better.
Hope this helps.
Craig