I have a 307G2 that had a timing belt issue. My solution was to shorten a #224195 belt ( E Bay $13.36 AUD in 2019 ) by diagonal splicing, super gluing ( Loctite Super Glue Power Flex, E Bay $ 11.35 AUD in 2019 ) and pining with dress makers pins. The #224195 belt is long enough to practice splicing with the off cuts, however I purchased 2 belts just in case I messed up with my first attempt. It was so easy to do that I now have a spare belt. Lots of information showing how to splice toothed belts on Google.
Machine has been working perfectly since 2019 and belt splice still looks like the day it was done. Have a few photos of belt before and after splicing, all too many MB to include. Happy to e-mail to any one interested.