Using a degree wheel to find port timing & durations on a chainsaw - ported Husqvarna 350 build

Here's a link for setting up a degree wheel
• How to set up a degree...
To calculate port durations from port timing numbers.........
Exhaust : port timing number multiplied by two and subtracted from 360
Example 102° x 2 = 204° 360 - 204° = 156° duration
Intake : port timing number x 2
Example 67° x 2 = 134° duration
Blowdown : Exhaust port timing number subtracted from upper transfer timing number
Example 126° - 102° = 24° of blowdown