Initial timing with the Mas-Flo SPOUT connector disconnected will probably be around the 14 degree point or wherever the information you got with the Mas-Flo says to use for inititial. Once you get the engine up to temp with the SPOUT still unplugged adjust to the timing setting that you're shooting for.
Once you plug the SPOUT back in you won't be able to use a light to determine what the full advance is. With the spout plugged in the ECU controls the timing and changes it too quickly to use a light.
The A9L ECU that Mas-Flo uses has a fixed program that can't be changed in the unit itself. To make any adjustments to the program you'll need and aftermarket chip plugged into the J3 port on the ECU. Your Mas-Flo should already have an aftermarket chip plugged into the J3. That's what Mas-Flo uses to customize the tune for your particular engine setup.
There are a couple of aftermarket units out there that allow you to monitor what the ECU is doing. Tweaker and Quarterhorse are two that come to mind but to use them effectively you need to have the existing J3 chip read and the program made up in a form that the aftermarket adjustable unit recognizes.
Once you're at that point the learning curve for futzing with the program is horrendously steep. there are somewhere in the order of 150 or 200 parameters in the program and, in general, changing one of them will effect several others.
Best advice is once you get the engine running take it to a tuning shop that understands the A9L program. They aren't particularly easy to find but there are some out there. Unfortunately it will take some digging on your part since most of the "tuners" out there are pretty focused on pure top end power and have no idea how to keep the system drivable once it's tuned for insane top end output.
Best advice I can offer is to get the engine running and then see if you can live without getting into it further. Mas-Flo is pretty good at providing a solid middle of the road tune with their system right out of the box. If you feel you just have to get into it and can't find someone locally who can make the adjustments you want be prepared to a lot of midnight
oil learning the A9L.
DonC