Dennis,
This assembly is tight - but here's what I did. I mount the tanks using the outboard -most (3rd) notch of the 10 inch bar. I collapsed the regulator bracket L shape ends slightly to allow the bar to go on top of it - instead of below it as Sunline had it , also lowered the bracket a bit more by switching the position of the retaining nut on the all-thread piece from above the frame - to below the frame. This allows the pigtails to route downward below the widest part of the tank rim where it begins to curve away from the regulator a little. The pigtails also run slightly in front of the tank rim - but even compressed against it - it appears the bend is tight but not damaging. It is still tight but acceptable. As you can see from photo -- (my wife will post)
To remove the tanks :
1. unscrew the large wing nut and remove the bar completely
2. unscrew the pigtails from the tanks (big green plastic nut)
3. Lift the regulator bracket off of the all-thread at the topmost mounting hole and move it aside opposite the tank you wish to remove. (NO need to pull it off completely)
4. pull out the tank - over and aside of the battery (which should be positioned with long side of box running front to back unlike your photo )