i was looking for information on the 401x2 (single bay version with 2x pumps). i know there was a lot of bleed issues with the 402/452 when running two pumps - i was just wondering if there were any issues with bleeding the single bay res under similar conditions. (martin's 401 review was only single pump)
I've done a dual DDC325 setup with the RP401X2, and well, it is not to difficult to get it to prime. have my reservoir vertical though, look at my project log for an example.....last few pages.....

Basicaly I add water to the res, start the pumps, 1-2 seconds stop them, add water, and after 10-15 times, system primes really well, and water starts to flow. After that, not many hassles, bleeds pretty well.......if you can prime the majority of the system with water beforehand, it will be easier still.

Have fun, and let us know how it goes

To OP: Soz for off-topic, Skinnee.