I had decent seeing and transparency for about half an hour after setting up last night with the 6" Cave on the GM8. I tried my 40mm Optiluxe with a 2" barlow but it didn't work for me, most of the time was spent with a 28mm RKE.
At ~20, the Trapezium resolved into 4 distinct stars, but the exit pupil was too big to be optimal for seeing the nebula. Swapping in the 12.5mm Meade RG in the barlow showed some astigmatism from miscollimation and eye position was extremely critical. I think I caught the F component, but decided to go back to the RKE for sweeping.
The Pleiades and double cluster were both framed nicely and were a substantial improvement over my 3" refractors. Coma and astrigmatism were noticeable but not distracting. For a 3 element eyepiece, the RKE handles a fast scope extremely well.
Star color is much more vibrant than in the small refractors, something I'll start taking notes on.
Before heading back in to defrost, I caught several more open clusters in the southern and western sky and found M81 and 82 just rising over the trees. I could see some structure in 81, but 82 looked like elongated fuzz with a slightly brighter center.
An hour later transparency went downhill sharply as ice crystals started forming high, wispy haze. Even the Pleiades lookeded like a dim smudge. I took a look as Sirius just to see the atmospheric chromatic aberration, there but not much, and closed out with Polaris. At 20x B was clearly visible right next to the primary, confirmed by bumping up to ~50x with the RG.