What is the minimum clearance I need between the truck cab and camper overhang?

[Sterling1]

I'm getting a 2024 Ram 3500 DRW long bed crew cab truck for my 2000 Bigfoot 10.6 truck camper.  My measurements show I'll have about 1.5" clearance between the truck cab and camper overhang at about the center of the cab.  I'll have about 1/2" at the shark fin antenna but I plan on relocating that.  I'll have a better idea of the clearances when I get the truck.  

What is the minimum clearance I'd need at the center of the cab and at the very front of the cab to accommodate frame flexing?  

Thanks for any input

[Sterling1]

As far as I know the crowned bed is limited to GM trucks but I'll verify the Ram bed isn't crowned with a straight edge.  

[MORSNOW]

GM pickups have much less flex than a Ford, you can search frame flex videos and see the drastic difference.  A standard rubber bed mat will also provide cushioning while helping hold the camper firm, the problem lies in many go cheap and heavy by using horse stall mats that are three times thicker and offer plenty of rocking potential.  My setup is a standard rubber bed mat and an aluminum superstructure camper with minimal movement up top, but it still does move some.  

[Grit_dog]

Fords were flexy until the 2017 Super Duty chassis. Before that they still had a c channel frame where Dodge and GM went fully boxed in the early 2000s new models. 

[Sterling1]

I really wanted to make a GM truck work since they will let you get a gas engine in any trim line.  The problem I ran into was the 2024 Truck-Camper Loading guide was completely wrong for the cab height.  It showed the cab height as 40.8" but I just happened to measure the cab height when I was taking some other measurements and it turned out to be 44" and that didn't include the shark fin antenna.  I'm glad I found out before it was sitting in my driveway although I could have dealt with it.  The ram is 42.5" which was enough to sway me that direction (among some other things).  Ford was higher than I even wanted to consider.  

I'm hoping to be able to trim my current K3500 bed mat to fit the Ram.  I'm also hoping that the Ram frame flex is low enough to let me get away without building a platform.