I'm not familiar with the SK's but 15" seems like alot of propeller. I've had real good luck with the Top Flite wheels. They're about 4.5 " in dia. They're metric hubs so you need to "carefully" run a drill through them. The hubs are made of brass so they cut easy. The spokes kinda go with the World War One Eindecker/Stick and they don't catch alot of wind as they have a narrow profile and being spokes there isn't much of a side profile either.

The Fults tooling nose gear was one of the best things I've done for this model. It's super tough. I used the OS engine mount and cut out a piece of Plastic Delrin that mates to the stock fire wall blind nuts. If (When) I tear one up I can swap the whole front end in a jiffy....
I also went with real good hardware/horns/carbon pushrods/etc. that can be re-used and transfered over to the next victum.

One of the best things (I think) about the GP sticks are the replacement parts, much less exspensive than the Ultra stick parts. I tend to get "over confident" and buy extras. But that's how you learn right.