Considering the purchase of a Crosman 2300S - I know that these come with a Williams FP notch w/ target knobs. I am wondering if anyone has adapted any other sight (Bomar, Champion, or such) to these guns. Ideally, I would like to have such a rear sight and a adjustable-post globe sight to help my aging eyes. Any ideas ??

I too am in the aging eye category (as are most IHMSA shooters these days) tho I had cataract surgery a month and a half ago and WOW, what a difference. 20-15 in the left and 20-25 in the right. I don't own one of these guns so I can only speak in general. I did not get to handle it, but I've seen the PCP version with a Gehmann rear sight (590L) so to be legal under production rules the receiver would have to be factory dovetailed with 11mm grooves as all of the Euro sights require 11mm. The same gun had an Anschutz globe sight (9759) on the front (which, by the way, will fit a standard 3/8" dovetail). From the rule book: "16. Production handguns may be drilled and tapped for scopes and still be used in the Production gun categories". I personally see this as a gray area. Are scopes and sights/bases synonymous? Can the front of the barrel be drilled and tapped for a commercially available dovetail base (of a proper height to bring the globe in line with the rear peep)? Champions Choice does sell such bases. Anything custom is a no-no. The person that owned this gun has been shooting for a long time so I'll go down the road that what I saw is legal.
On a side note, consider a globe/aperture in lieu of a globe/post.

I'm not an AIR person but know there are some front sights that use a band that clamps to the barrel and this should be Production legal since there is no alteration to the gun. Champions Shooters deals with some sights like this. Installing a scope base by drilling and tapping is legal and at least would give you a Weaver type base on the rear to mount an aftermarket sight. Don't forget you can use more than one adapter mated to another adapter to mount sights as long as the adapters are not altered. I have seen some weird combinations of multiple adapters to finally mount the desired sights.

Thanks for the input ! I am really not worried about it being "Production Legal" ! There is a group nearby that shoots a combination 10m Olympic-style match, combined with a air pistol silhouette match. What I am suggesting here is allowable there. If I ever shoot an IHMSA AP match - I will just shoot it in Unlimited ! PS: I ain't shooting the Olympic-style match !!