Help figure out ratios

Well I see what you are trying to do now, but you are doing it wrong. You should be turning the front shaft and counting splines, and turning the rear shaft ONE turn.

So working backwards from your figures for 1st gear, 1 turn at the front and 12/30 for the rear, this equates to 1: .4 and you need the "other way around."

This APPEARS to be a 2.66:1 first gear, which with your figures works out to 1.06 instead of 1. This COULD be because you made that much mistake when trying to count the splines.

What I would do for accuracy is turn the rear shaft either 5 or 10 turns and count the front. 10 turns would give you a "figure in your head, IE 10 at the rear is 26.5 at the front, so an easy 10:1 figure.