This is how I assign strike numbers. 1st if it's recon, and I'm setting it over a large area I will set it to 99. This will create as many recon flights as possible, and I leave the requested numbers on auto. Strat Recon I leave on auto.
I think that runs the risk of 'burning up' your allotted flight miles for the week before the week is through, doesn't it (moreso I would expect with ground attack than recon, but under the same principle)?
I've set the intensity to 'high' and seen ADs run out of aircraft late in the week (e.g. bomb days 1-5, but not on day 6 or 7).
Ground Support and Naval I set my strikes to 99, to maximize my patrols over the area. I'm not sure if you've noticed this or not, but when you fly to your naval AD, your planes are creating a 2-4 hex wide path as they fly to the target. If you have it fly by other areas that need some naval while getting to their patrol, they can create additional naval interdiction on their route. I like to fly them near ports I want cut off by just adjusting their path. Multi-tasking!
Yes, I actually mentioned in my AAR. On turn 2 one hex on my B-25 Naval Patrol route was contested from a 3 to a 2, so the path to the patrol area over Messina failed to also block out Palermo that turn.
What I've seen is it accumulates over the route from the staging base to the target, so I will setup my route/staging base accordingly.
I have not see it accumulate in the adjacent hexes on the path, but I bet you could put two ADs on the same path to good effect.

"War is never a technical problem only, and if in pursuing technical solutions you neglect the psychological and the political, then the best technical solutions will be worthless." - Hermann Balck