I don't know why you won't consider Champion Photographic's chemistry.
And I never said I wouldn't consider another developer, I'm just not ready to venture into other stuff yet. I've been stuck on Kodak since high school, it's all I've ever worked with. And now I'm having to change my processes, albeit by personal decision. It's just easier for me and more comfortable for me to use a major player like Ilford right now.
A replenished developer works best if you are processing film on a regular basis. If your developing is sporatic then a one-shot developer might be best such as Kodak HC-110. The concentrate keeps for a long, long time. It's also quite cheap when you figure how many rolls you can do with a single bottle ai 1+31 and higher dilutions. Look at the following website for information on this developer. www.covingtoninnovations.com/hc110
What does a replenished do, anyways? And by that I mean chemically.
Someone else may very well be marketing the Kodak stuff soon.
And as for ID-11 dilution choices, Ilford's fact sheet lists times for using stock ID-11 (7.5 minutes), ID-11 diluted 1 + 1(13 minutes) and ID-11 diluted 1 + 3 (20 minutes)
I have used replenish XTOL for over two years without a problem.
Before going to a replenishment regime I'd recommend first reading about it as discussed in detail by Kodak in this excellent publication (including how exactly to do it for a variety of developers including XTOL should you decide to go that way). Pros and cons are discussed. See pages 15-17 (this entire publication is an excellent reference though):
Gerald's HC-110 suggestion is worthwhile considering.
DDX is an excellent developer. It works fine at 1+9, but make sure you still have an adequate amount of concentrate in the working solution to develop the amount of film. Refer to Ilford's instructions - although they do not explicitly indicate the amount of concentrate required per area of film.
In general, more developer is better, and skimping is not worth the potential price.