I need a parts expert please

Oh I get it, I have an MSD and running FiTech myself. I'm just saying I would use the same PN to dial in the phasing as you are going to actually run. If you just use a cap that's "close", your results will just be "close", and you can get close without even visually phasing it.
I agree, the issue I'm having is I'm using a Crane ignition box. When I set the phasing as "close" as I can, under high load, low rpm, I get a miss fire as if the multi strike is continuing long enough to hit the next cyl. When I disconnect the box and run straight from the FiTech (single spark) the miss is gone. That's why I want to "see" the phasing position to confirm it's correct. thanks Larry