I've had my main tanks and the aux tanks out. Be sure you follow the service manual, make sure you support the wing to remove the upper wing panels, they are structural. Not remembering if you need to support to just access the inboard Aux tank but the service manual will know. Those upper wing panels can be difficult to remove. Plan on stripping / breaking several screws. The panel tucks under the boom skin and is a bugger to RnR
http://www.337skymaster.com/messages...?t=2309&page=3
see photos in post above