Also installed a holley hyperspark EFI box about 2 months ago, I went for this one because it was as simple as it gets and its intended to be used on EFI systems. I did not want nor needed further adjustments or functions, just amplify the spark as it came out of the Proflo 4, single spark, capacitive discharge. You can see (hear) in the videos the difference in spark power.
I placed the spark box in the place where I hade the procomp vacuum canister, after realizing the cam provides enough vacuum I got rid of it, the simpler the better, in my opinion.
Lots of info packed into your posts. Are you saying you ultimately moved to a Holley Hyperspark distributor WITH the Proflo 4? And just adjust the timing settings in the handheld and leave the distributor alone?