Also if you have a metric ruler, 4mm spacing would give you very close to 6 Tpi. If you need to accurately divide an inch into 6, draw a right-angled triangle with one of the short sides 1″ and with a 1.5″ hypotenuse. Then mark off 1/4″ points on the hypotenuse and drop them perpendicular onto the 1″ side, to leave you with six evenly-spaced points on the 1″ line. Obviously you can extend this technique for any Tpi by choosing suitable lengths and divisions. I recall that Paul Sellers demonstrates a similar trick for dovetail spacing in one of his videos.
Going back to the original question – if the existing teeth are evenly spaced and you just want to change the rake then you may not need to file them off completely. In which case if you still want to use Paul’s jig, you should transfer the tooth spacing from your blade onto the jig using the trick he demonstrates with a hacksaw blade.