Need tank relocation advice!

[Gapp]

I have the Blazer complete tank relocation kit from American Classic and I removed the smaller crossmember to allow for clearance. The only thing the instructions say is that you may have to trim 1/8"-1/4" off the bed frame support for clearance. I thought the flange was supposed to sit up against the frame w/ some gasket material in between to prevent squeaking. I measure 6 and a half inches from top of flange on tank to top of tank. When I transfer the measurement, that equates to my having to cut like 2-1/2 inches off the bed cross support. I've exhausted my searching for a week and all I can come up with is some blurry pics showing the finished product. Can someone please help me figure this out? Thanks in advance! -Danny