That's really not a bad image. That said, you aren't happy with the bit of bloating.
I've never used the Infinity and you didn't exactly say which scope you were using but at a guess?
I'm betting you used the Tele Vue 85mm. That's an ED-Doublet and I would expect that when used for AP you'd have some bloat due to IR not being brought into focus at the same focal plane as your other wavelengths. This doesn't mean you cannot or did not get a good image but it just doesn't quite do what a great triplet with field flattener and all that would do. The ED-Doublet also isn't as heavy and it isn't as expensive. . .
But that isn't really quite all. . . Your camera has pixels which measure 6.45 microns. Your Tele Vue 85 has a focal length of 600mm. These are not necessarily bad numbers but together they may or may not be so good.
If one assumes you had fairly average "seeing" of 2 arc-seconds then by typical calculations your sampling should be at about 0.67-1 arc-seconds in order to have best detail and tight stars. Given your pixel size and focal length your actual sampling is right around 2.2 arc-seconds which means you are under-sampled and cannot expect to capture all possible detail. But this is often just not a big deal depending on your goals.
Not really knowing your software and camera very well I'm not sure about another potential issue. Your Full Well is about 24K but your ADC is apparently 16-bit which (as a non-guru) just seems a bit out of proportion. And you have a fairly noisy sensor. You add in the fact that I don't know what your gain was or what your actual bit-depth would be at that gain - you could be over-saturating and your software could actually be handling some of that for you.
Net effect is that I can't tell for sure why the stars are a bit bloated in this case but you could potentially clear things up a bit by using an IR filter, shortening your sub-exposures to avoid saturating.
And if you used the camera with the 8" SCT? Since the corrector plate is only doing weak refraction you likely needn't worry about an IR filter. When using even a 0.63x reducer at 2 arc-second seeing you would be only mildly under-sampled.
But then, going with the 8" SCT would mean that your FOV would be narrower even if it fixed a few problems. A little bloating may be worth it in order to get the wider FOV which comes with the shorter focal length?
If you are using the SCT already then things get a little more interesting.