Denis, I think you should be fine with Kodak chemicals, after all they invented the C41 process.

Regarding a pre-rinse for C41 as mentioned earlier, I'm not too sure that is a good idea, especially if you maintain the 3'15" first bath, which is the developer. Having a pre-rinse with C41 would mean a slightly longer time required in the developer.

With the developer time being so short as it is, development time, along with active developer strength is really critical. By doing a pre-rinse with C41 you will be changing, what is an already tight process, to an unknown variable. I have never seen any commercial C41 process anywhere, that has a pre-rinse.

To put the time thing into perspective with C41, adding 30 seconds to the first developer time, is a push of 1 stop.

I have done a considerable amount of C41 in my CPE2 (with lift) and found that a strict 3'15" followed by a stop bath (optional), works wonders for consistent roll after roll or sheet after sheet, of C41 developing.

Once you get a couple of processes under your belt, you may even think about push processing, although if you're shooting 4x5 I would think you wouldn't need to push the film. It is things like this that make developing your own film really worthwhile, plus you shouldn't get any scratches or footprints on your film.

By maintaining a very strict developing process, you can see the effect of what a 1/3 stop (approximately) over exposure on grain size on every sheet/roll does (slightly finer grain). On the other hand, a very slight under exposure will coarsen the grain slightly. It is these variables, along with extremely consistent processing control, that can make really great technical control of the C41 process possible.