For an ash snare, I would play to its strengths, which is attack and projection. I would do a double 45 with a hint of a flat spot at the apex that you can round off by hand with some 320/400 grit sand paper. Offset it toward the outside of the shell, maybe 2 plys in with the 3rd as a flat (it all depends on the shell layup, thickness, number of plys, etc). This will give you a bit of control on those sharp harmonics so you don't need to use moongel, but will still give the drum a penetrating rim shot with a crisp crack.
I did something like this with my Pecan stave shell. I cut the reso side with the same dimensions, but cut the edge to basically razor sharp. No rounding. The drum is f'n amazing.
It takes almost nothing just to take that sharp transition from the 45 to the flat off with 320 sand paper. Maybe a few quick rubs knocks it off. All you are trying to do is soften the transition from 45 to flat. You want to keep most of that flat area as it will help with the wonky overtones and tuning difficulties you can get with sharp double 45's. I think I left ~ 1/16" flat on my snare and blended the transition. Its hard to photograph bearing edges because the depth of field gets so darn small. In any case, you really don't need to do much massaging to the edge with the sand paper to shape it. 320 to knock it down, 400 for the final polishing. With something like Ash you really dont have to be super careful. Its a tough wood, like the Pecan snare I did. Its not like sanding poplar where you really need to be careful you dont sand too far. Just go slow. You can always take off more. Its just really hard to put it back.
Reso edge is as sharp as I could get it. Here is the only photo I have showing the bottom edge:
You can see its a bit sharper than the top edge. Also, I dont recommend this type of snare bed on your every day snare. This bed is specific for this type of strainer system and wires.
It all depends on the drum, its shell construction and how I want it to sound. Reso heads, like batter heads are more sensitive with the less and less shell contact they have. The less stopping the head from vibrating (less shell/head contact) the easier it will move with the slightest touch. Because of this, sharper edges will lead to more sympathetic snare buzz. Some of that can be tuned out with snare bed size and depth but that head is just easier to vibrate when its riding on a sharp bearing edge. If sympathetic snare buzz is a problem for you, something that gives you more head/shell contact might be what you want to tame it. If you want more sensitivity, go with sharper edges. Less sensitivity, rounder edges.