Here's my take on your questons (please keep in mind that while I have done some home RA4 I mostly do R3):
Originally Posted by dweccl
Oxidation when pouring the chemicals out of the tube: it undoubtedly does oxidize the developers, but I just replentish 25% above schedule and it seems to work fine. Except for the blix. It needs oxygen.
Temperature control is most exacting when developing film, as there is no coming back from a mistake there; you can always reprint paper.
With RA4 the developer tine is very short (a minute) so I've always had a bigger problem with getting the timing right than getting the temperature right.
Tubes don't need to be completely dry, just dry enough to get the print in. If the tube is very wet it will stick, and if there is liquid pooled at the bottom you might affect the development of the paper that has been wetted longer, especially if you are not wetting the paper very long before adding the developer.
Anyway, here is my page on color chemistries: http://wilson.dynu.net/chemistries.asp