Hi Dan
Congratulations on introducing task syncing with Google Tasks. I am using it but it does provide me with some problems. I need to sync my tasks across platforms (PC, Ipad, phone) and a lot of my tasks are recurring. Google Tasks does not support repeating tasks but I can add repeats in Vueminder. But, of course, the repeating information will not sync. So if you mark the task as completed on another device (e.g. phone), the repeat will be lost in VueMinder. The only way to avoid this is to only complete the task on the PC which isn't very convenient.
Are you still considering Toodledo sync which supports repeating tasks.
Philip