Ive used sks 55's on my 26 in. bike with 2in. tires on it, but purposely left a lot of room for mud clearance, and if I ever put slightly wider tires on or similar width but a more knobbie type tire.
I have 1.5in tires on the bike right now, and the space does look a bit goofy, but I dont really care.
the issue with the sks stuff, while its really well made, is that the attachment system for the struts to the fenders is made in a way that you have to physically cut the struts to the length you want. Other fender systems have the strut ends coming "through" , or actaully passing through the anchor points, and then you just tighten the bolt to where you need the fender clearance. The sks anchors have closed off tops, hence the need to cut them.
I guess the idea is that its a cleaner looking end result, and perhaps more robust, but Ive used PB type systems before and they dont come loose or anything, so I dont see a downside to them (and of course, I guess extra long bits sticking up that could snag on stuff--but you could easily cut them a bit.)
as much as I like the build quality etc of the sks ones, and the really nice finish of the silver ones I have, "regular" anchor point systems will be easier to adjust if you really want to change tire sizes while keeping a closer tire to fender distance.
My bike was set up as a tough, go anywhere type bike, so it didnt bother me with teh big gaps between tires and fenders.