I initially assumed red was worse than yellow. I've been testing a bit over the last couple days and I have a tentative theory.

It seems to be that obviously white is the most stable. If you're going to do Rapid synthesis, this is the only safe place to try it.

Yellow is bad. Just all bad. Higher chance of failure. I always select Wait for yellow.

Red is probably also bad. An increased rate of failure... perhaps. I find on Red it's either a complete success or a complete failure (explosion!) most of the time.

The flashing status is really random. I'm only guessing at this point, but the speed and colours you see might determine the general success rate. I've noticed times when it's mostly yellow and red flashing I've failed more. But overall I've failed more in general when it's flashing because I don't even try on yellow. The problem is using Wait will often land you on yellow or red from flashing.

What do you think?