Tomster... I agree with you. I would try the triple Se7en without the black powder first also. I am saying if there seems to be slow ignition with the flash pan lighting the triple se7en, then I would dump the black powder in first and then the triple se7en on top of it....

My friend who is an avid flinter recommended 5 grains. I see you even suggest as much as 10-15 grains with the clean shot. Living in Wisconsin, where it gets real cold, were shooting Triple Se7en powder one afternoon him and I. I noticed he would dump some of the priming powder in the barrel first and he explained that it makes the ignition time a LOT FASTER.