Depends on which rear element you are using and if you are focusing only at infinity.
I did a quick measure on my 8x10 camera with this lens. Nothing too accurate. Didn't set the camera up on a tripod. Just focused on infinity out my window.
With the 600mm element, I got @: 17" or around 430mm
With the 800mm element @: 21 3/4" or around 553mm
1200mm @: 31 1/2" or 800mm
This is not a super accurate test because I did not have the camera locked down on a tripod. It's simply to give you an idea of the bellows draw you need for your 4x5.
If you are focusing closer than infinity, then you'll need more bellows.
I haven't tried this lens on my 4x5 Acra-Swiss. I'd probably have to add a second long bellows to the camera and a thrid standard.
Hope this is helpful.
Boy was it wild hand holding an 8x10 in a dark room looking out my window with a 1200mm lens trying to focus on infinity. Worlds collide. Grin.