I tried different Flat 6A II settings on the TS72 last night and about 9mm seems to work ok. Outer field stars aren't properly round in a blown up image but look good at normal full screen size.
I had a closer look at the TS115 images and stars are a bit dodgy blown up so I'll need to fine tune it a bit too.
TS72, Flat 6A II at 9mm adjustment:
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