I have developed quite a lot of things in trays, one of the things I have done is develop RA4 in trays when I had some problems with my roller transport paper machine.
One of the real problems you may face, is the almost overpowering smell(s) emanating from a very large open tray(s) of developer and/or blix, not to mention your stopbath sitting in the middle.
I think you would be better off if you took PE's suggestion of using RART (Rapid Access Roller Transport) chemicals at the lower temperature of 20C.
When I did do tray developing I remember the pungent aroma, not to mention the concoction of steam arising from the heated developer bath. My darkroom was running around 20-22C so the baths were steaming and I decided to turn the heat off and make a go of it at room temperature.
The next night I ran at room temperature, after a series of tests I was getting acceptable results with a longish 1st dev time. I don't remember what it was, I could look it up, but it wasn't too painful. I used a "Jingle Bell" timer which only has time sequences at 30 second intervals. So the times would have been either 60, 90, 120 or 150 seconds or thereabout.
I also used gloves as in total darkness, or the dim safelight, which, with my vision wasn't great, I couldn't be sure of getting the paper out easily and/or within the processing restrictions.
I was really glad when I got my processor back up and running.
By the way, I was developing 12 x 16" paper.
Mick.