D3 belts need help

I'm building a d3 and was told to drop front diff gear to a 35t and the rear 22t center pulley to a 16t well now both belts are to long both diff are fully adjusted out. stock belts are s3m138 46t
And s3m183 61t

Think I found the length I need belt guide says 3racing belts are 3mm my belts say 3.5mm but when I Google aftermarket belts I'm finding s3m pulleys run a 4mm belt any help on this would be great can I run 3mm and or 4mm belts?