Dragline, sorry I was not trying to dispute your statement about the belts, just telling of my experience with the White.
The deck on my White is a mid-mount, but it looks like it would not be that hard to convert it to a rear mount or pull behind. The original design might have been to use as a rear mower. It has a driveshaft. I seldom use it now since I got the 7' finish mower so I may convert it to a 3 point to use behind my 2N.
Just checked and the belt for the 50" is routed the same way as the 60". It is not nearly as heavy duty as the 60".
Even though the 60" is an OEM option for the gt2055 it seems like it was an after thought. The gearbox on the deck sits a little too high, so if you raise the deck more than an inch or so the driveshaft hits hard parts of the mower.
And good luck to you Dane. Hope the website Dragline posted works for you.
1998 White GT2055 60" 3 pt
1999 White GT2055 50" 3 pt