If you like the size, I'd say it's worth trying one to see if it fits. Tricky because stated size can often be a ballpark estimate rather than a strict measurement, but I've noticed the Vittoria Randonneurs seem to state one size in normal language and a slightly larger size in actual measurements. 700 x 48 is listed as 50-622. Meanwhile Schalbe stays consistent, so a 47 tire is 47-622. If we assumed the actual measurements were accurate, the Schwalbe is 3mm less instead of just one. How that figures in when the tread is added, I don't know, but it's not as if the Vittoria's have no tread, just less. And Schwalbe's don't have a lot of tread, either, so it seems like it's worth a shot.

For my part, I think I was running 700 x 40 Randonneurs on my Trucker, and I was fine with that size. If you're doing pavement touring, I think you could easily drop a size. On the other hand, I also kept going with larger tires until I hit the limit of the fenders I was running, so I can understand the fat-as-you-can approach. I'd try the Schwalbe, and if it doesn't fit, try it without the fender and decide which is more important to you. If you like it, you might just want bigger fenders.