I have a good number of 2500 series tanks and reels both 35/120 and 4x5. I have in the past used these tanks on my CPA-2 processor as rotary tanks. I recently have tried and liked the Thornton two bath developer, but used Stainless tanks and reels to process 35mm. On Sunday I tried this developer with some 4x5 that I shot and decided to use the 2500 series tank and 2509n reels for inversion processing. I was able to remove the cog on one of the lids and have the large orange lid for this tank. I reasoned that if I was using the tank as an inversion method I would not need the black plastic end caps for the reel and left them off. As the Thornton two bath is not critical for agitation, my plan was to do a few inversion in the beginning and then just gently spin the tank back and forth a few times each minute. It seemed to work OK, but a couple of the sheets moved during processing and where the end touched the other sheet I seemed to have a mark. I was thinking that the black end caps would impede the flow of developer with my regimen of spin agitation. I know that the caps are very useful for rotary processing with the 2509n reels. How do other people use these tanks for inversion processing of 4x5 film and for that matter 35 and 120.