Thanks for the additional feedback, everyone. I'll definitely look into bringing in the fenders closer to my tires, as even I thought it seemed like a lot of clearance. That's about the closest I could get them with how much (or how little) of the stays I cut off, though.
Luckily, I have no plans on boxing up my bike for shipping any time soon, as I'll be heading out from my home when I begin my multi-month tour near the end of this September. I mostly plan to stay on roads, but I imagine I may encounter some dirt paths or gravel roads, so I surmise I'll want to keep a little extra fender clearance, though perhaps not as much as I have now. I'll also look into the possibility of my toe hitting the fenders from different positions; thanks for the tip, tsteven4!
Also, just to note...
I am disappointed with Peter White, he should know better and refund your money.
While I used the information I found on Peter White's site to choose which SKS model to purchase, I ended up buying my fenders though Amazon. So, I guess just use this experience as a heads-up to others that Peter White's information on SKS fenders isn't entirely accurate.
Lastly, thanks @happyriding for the link to the "bikes with fenders" picture collection. I can see there's a lot of variation in clearance positioning, so I'll just have to do a little more tinkering to find out what works best for me!