Thanks Martyn. My thoughts on trying the 742 was that going deeper into red I may have a bit more stable capture, and I think it kind of 'worked'. Wed and Thursday morning are looking really good so I will try again. This is the 685 capture for comparison:
(I do not pay much attention to what aperture is better with a specific filter. I got some stunning Venus UV images earlier this season with my 8" (which in theory should not have been easy), so it is all about experimenting and trying, at least for me.). I think with new generation cameras and their IR sensitivity, I think we can pull more signal even with the smaller mirrors.