I am partial to the steel tanks myself. Once you've used a practice roll of film and closed your eyes loading the reel, it's really not too bad, you just have to get used to the curl of the film as the reels take it up. If you hear a click, back out and be consistent loading it again.

A thermally adjusted water bath to keep your processing chemicals is the key to temperature control. Let it all stabilize for a few hours and all will be fine.

Having worked in a lab, the way we did this stuff was in a longitudinal processor. The film lead was attached to plastic cards, and a gear train would pull the card through the processor (right from the canister, in a light sealed box). The multi-stage process was timed via the length of the film travel, but has been pointed out, the critical thing is the initial color development, and the reversal processing. Once you stop the process (ph change), no further development takes place, and it's a lot less time-temp dependent.

I still remember the smell of these chemicals when we cleaned the processor weekly, the smell of glacial acetic acid is like the most overwhelming vinegar your nose has ever wiffed. Those chemicals will stain badly too. Also chemicals have a short shelf life, especially the developing agents so best just to mix a one-shot usage, or process a lot at a time.

I used to process my own more out of interest than out of need, or to play with push-processing, something commercial processors are not always fond to do. The way we did it was to turn up the temperature on the developing tanks (end of the day after all the runs), let it stabilize and do it that, it was not physically possible to change the rate the film moved through the processor.

Hope this helps.