I want to replace a Dimarzio D activator with 2 single sized ( Air Norton S & BC -1 ) and was wondering if anyone has ever done this with pickups so close together. I cant find out from Dimarzio if those pickups are shielded enough for this situation. Also will a 5 way switch fit onto a small hole made for a 3 way switch with the same outer ring?
pickups arent shielded, and they dont have to be. you can put them that close together.

not sure what you mean by the second question. a 5-way blade switch is not compatible with the mounting holes for a 3-way toggle switch.
yeah that'll work. be sure to get a setscrew knob with a good grip or it may be hard to turn the switch.

that has twice as many poles as you need so if you want you could probably get some fancy wiring going.
You might have a problem fitting them in the cavity, as single coils have a little thingummy on the base.

If you have two right next to each other, the extra bit on the base will get in the way.
Did you mean sort of staggered over the plate? It might work, but there'll be a big difference in heights.
If they come in a lefty version, I would get one in lefty and turn it round. That way it'll be a righty but with the projection from the plate going towards the neck rather than the bridge. The two pickups will then fit properly against each other. However you will probably need to make the pocket bigger, and if you don't have a pickguard on your guitar the pickup rings may not cover the larger hole.

Also the on lefty one you can probably just pop the cover off and flip it as well so that the writing is still the right way xD
That is very smart because those little plates will go where there is extra space inside the humbucker ring.
Quote by Invader Jim
flip one of them around. "back-to-back" so to speak.

doesnt matter if it's "lefty" or not. thats not at all how pickups are made or how they work.

I didn't think so, seeing as it's just a coil round some pole pieces, but I thought I read something about a lefty pickup somewhere. It was probably just that the cover was flipped so that it would read the right way (if there was writing) on a lefty guitar, but hey.

And it probably would make a difference on a strat-type SC with non-adjustable pole pieces set up to balance out the g-string output, but not on rails at all I guess.