Attached is a degreewheel you can print and use, it’s made in 300DPI so the size is correct when you print it. It’s 100 mm outside, cut the inside at 77 mm from center and it fits your Piaggio engine.
A very helpful tool to calculate your cylinder port timings on any two stroke bike, from mm to degrees BTDC and reverse. Let me know if the link is dead.
I’ve made a spreadsheet that you can use to calculate the ingition timing, to convert mm before top dead center to degrees, and reverse.
Another spreadsheet i’ve made, to calculate the speed of your moped at a given RPM.