I have an EXOS2 PMC8 mount, and I like it. I use it strictly for Astro Photography on DSO's - I will work my way around to the planets eventually. :-)
As far as the form factor of the TPO Newt is concerned, I think that would be ok for planetary. We have a couple of folks on the PMC8 support forum using 8" Newts on EXOS2's. They know they're pushing it for AP, but that said, they seem to be getting by, so 6" should be ok. There has also been Q&A on planetary from various folks.
You can do due diligence at the support forum here: https://espmc-eight.groups.io/g/MAIN
For reference, I'm using a 102mm f6.1 refractor, about 28" long counting camera, and about 13.5lbs of payload counting cameras, guidescope, etc. If I do my part and conditions are reasonable, I have no problem guiding round stars for longer exposures than my waterlogged, light-polluted skies will let me use. It's fine - but I do have to do my part (gear and belt adjustments, balance, etc. - not hard).
The ES PMC8 mounts (EXOS2 and iExos-100, plus G11) are a little different from the ones usually recommended by the advisors here, but there are good reasons for that and they can do well.
By all means, do a support forum post to check your proposed config for planetary work with folks that do that, but I think you'll find it's ok.