OK I'm gonna cough up for a cognito conversion Stem what offset

[The Tin Man]

Thanks for the advice, I'm committing to a cognito conversion stem. I have a Radian swing arm which increases track by 1 1/4 inches the R1 forks are about 1 inch shorter than stock. The offset on my XS Fork is 30 mm.The conversion stems come in 30mm 45mm 50mm and 60 mm they suggest the last 3 for 19 inch wheels any advice on which one?
I know that there are mathematical models to look at the geometry but I am dyslexic and numbers make me see in blurred vision.