Drain plug on the MTX is facing the firewall on the tranny lower left side. However, that fluid AFAIK has never been used by anyone on the site, usually most recommend Royal Purple SyncroMax, though some have recently been saying ATF, though I personally do not think the ATF (which is the current Ford recommended fluid) has enough friction modifier in it for the manual, original Ford spec was manual trans fluid with some of their friction modifier, known around CEG as Ford "honey" due to its color and consistency, added in. I have over 40K on my RP SyncroMax and roughly 30K previously with the original fluid.
I love the RP as it used to be difficult to shift into first and reverse in cold weather and had an ambiguous feel, like shifting a butter knife through a jar of peanut butter, the RP changed that and then my B&M shifter made shifting even better.