The 2820 test drum and the 2521 film drum are the same tank, but with either a sticker for paper and capacity or film and capacity. The 2840 print drum is composed of two parts; the smaller part is the 2820/2521 drum, so if you see a 2830 print drum you can use this as it is effectively the same drum as the 2551 film drum. This drum allows the usage of two 2509 reels. Use 600ml of developer and drum, but do not attempt to use a bigger tank like the 2840 print drum with three 2509 reels. The amount of solution required is too much for the small motor on the CPE2 units. It will work for a while, but I have personal experience with a few friends who have burnt their motors out.
So you have the drum situation covered. However you will require a centre core to seal the light out. The centre core from the 1520 film tank, is the same centre core required for using one 2509 reel, you will need one of these.
The 2509 reel, (which is what I have) will hold 6 sheets of 4x5 film, I use 4 sheets only as I found there were evenness of developing with the 6 sheet in film with huge amounts of sky or similar. The 2509N reels may be different; you will have to check your own situation out.
I have the 2508 film loader and the appropriate film guide for 4x5 film. Whilst I can and have loaded without the 2508 loader, I find the loader and guide to be ideal for my situation. If you really wish to ensure repeatability and a minimum amount of film holding with hot and sticky fingers, you may find the film loader to be good for you.
Whilst the amount of solution required is 270ml, I use 300ml for ease of calculation and an added safety factor from the Jobo chemistry capacity.
The CPE2 with lift is one of the better ways to develop film, especially C41 and E6 with their precise times and in the case of C41, short developing time.
Mick.