The garage in which I have started printing RA-4 is decidedly colder that the postively Caribbean 15 degrees which you are presently enjoying in your bathroom.
I've ditched the processing drum - far too fussy - and have been developing in trays by using an 8x10 tray (containing Kodak dev/replenisher stuff from the brilliant AG photographic) placed inside a 12x16 tray that is regularly topped up with hot water. The paper is supra endura.
Although far from being a scientific process, I've been able to get some really good results and the filtration settings have been just about constant across the two films that I've printed from so far (Fuji 400 and Ektar 120).
I'm no expert but this has worked well for me. I think the best advice for anyone starting out in RA4 printing is simply to search about the forums on APUG. There's a rather good 'colourman' article knocking about which I found very helpful, and loads of really good advice from people who know their onions. Good stuff.