Paul - the University of Western Sydney has an ST-4020 with filters that they want me to try for them. They've owned it for a while but haven't had an equatorially-mounted scope to use it on - having an alt-az 14" LX200 in a dome. I've offered to use it for a while (
) on my FS-102 - so that might be something I could help you with when I get it. It'd be close to your TSA in terms of resolution, etc.