hi all got my benchwork complete ,my ? is turn radius i know 22 inch is recomended and 18 is minimum.whats the best way to mesure this my starter set came with a 36 inch oval .im going to use cork and flex track .whats the best way to get the 22 inch radius i have my blue foam board down .and im ready with a sharpie .if only i had a giant compass .will a string attached to a tack work?and if so will it give me that 22 inch radius ,hope this isnt to dumb a question..newbie with a really nice bench and a bachman flyer 
