I had a deck put on our F350 chassis cab. I consulted the site below to find the spec for rear tire jounce - upward travel
ON EDIT in this case from an unladen state. Loading can reduce remaining travel. For eg a 2018 CCSB PU 4x4 with 10K GVWR it lists 5.6" + 0.5" for clearance. (see doc pg 26)
https://madocumentupload.marketingassociates.com/api/Document/GetFile?v1=4311733&v2=060118102504&v3=60&v4=45dbbe577f9d338234fc31eecf98ec222b8c1946a09647cffb88778c&v5=False
Our deck was put on with the stock tires still mounted and I had plans for oversized plus be able to run chains so I added 1.5" to the oem clearance number. Of course many owners mod the rear suspension, that changes things and can be tough to calculate for.
Our much stiffer leaf spring main pack and overloads greatly reduce the chance of ever being at full jounce. Still, you might be surprise at how all that camper and gear weight can stuff a single rear tire in an off camber situation.
The first number for our model was 6.7", IIRC and we ended up with 6" between the tire top and deck bottom. That's loaded for a trip, all good. With 3 yds of soil in the bed it is less
As for looks, on ours the space above the rear tire does look a bit tight, especially compared to the fronts. Bear in mind some deck designs have some form of flare, edge or skirting around, or just at the top, of the wheel space (good for debris control). This can make the space appear smaller but can still work okay if the tire travel fits inside of it (may need a little wider deck to ensure this).
It's good to think about and discuss these things with your upfitter ahead of time, so no surprises.