Hey TSC! Glad you dig! By the way, I rarely get here now so best way to contact me is by email, but I will check now the PM that just arrived.
I don't expect to have the two machines in tempo just because both say they are at the same BPM, even if I was playing the same tune in both. This is true of every machine, even synths, there are many factors that help to this and in the case of the Amiga since I have one running on a 00@7Mhz and the other running a 030@50Mhz, I expect to have discrepancies.
As for Protracker, it may depend on if you are using VBL or CIA replay method. I'd say both machines at CIA timing with the exact same display output (both at NTSC or PAL) should pretty much stay very close in sync if they are at exactly the same speed, but shit can go off. After all, Protracker performs ridiculously fast on accelerated machines in regards to some functions, because the software uses the CPU ticks to calculate some shit (key repeat rates for example).
The version I am using of Protracker now has serial link, so when I hit play in one machine, the second one plays too at exactly the same time. It was developed to make 8 track MODs using two machines. This is the best way to check sync, using the same module on both. But this is just because I am testing some things, I want to use the 2.X branch in my project. We've been working with Delek this weekend on a new version of ProTracker more suited to this task I am doing in the video and it's working spectacularly, so I will make a new video maybe next week (after I test this new buid of PT in my gig on Wednesday).