More thoughts. Just back from gravel pit, light rain and low 40's here.
Fine tuned the zero on the S1, and shot it back to 50. Zero seems stable from yesterday.
So S1 on vent rib versus H2 in Scalarworks mount over action? If you have a vent rib the S1 will be easier, and if you have a Tactical model drilled for a rail, obviously the Scalarworks mount will be easier. Subjectively, I feel like the Scalarworks mount will be stronger as it has two screws and two posts, where the S1 is clamping the vent rib and relying on two screws pushing on the clamp piece. I put witness paint on the vent rib before this morning's session and it did not seem to move. However, last night the two screws seemed a smidge looser than I remember, but my recollection may be imperfect (I lean towards that I did not fully tighten them, as they are fine after shooting just now).
I prefer the improvements to the T2/H2 over the legacy micro the S1 is based on, in terms of more durable connections (per Bolke/Dobbs), the option of clear lens covers, and a cleaner dot. That cleaner dot probably is more of a factor at carbine distances than shotgun. The 2 moa H2 versus 6 moa S1 is personal preference, with the bigger dot nice for close charging furry things, and the smaller dot better for 75 yard groups.
Subjectively, the S1 mounted further away from my face seems nice for quick and dirty shotgun work, and not sure why but recoil seems more palatable with dot further away from my face. Both positions are plenty fast, and differences likely fall in the inconsequential increment territory. For field carry, the clean action with the S1 is a major plus.
At this point, I need to live with the S1 in the field for a month or two, and verify it holds the optic securely to know whether I like it or the Scalarworks conventional position for the optic better.