Hey Bobby,
I'm sure I've described this before, but I use tape to draw my patterns. I coat the bottom of the pan with tape , then add 3/8" to the pattern. The holes are laid out about 3/8" apart and bout 1/4" to 3/8" in from the edge. The back is then riveted to the pan, foam is added and beveled on the edge (3/4" foam HD neoprene from Foam and More 1925 W. Maple, Troy, MI 48084 1-248-284-0002). Tape is added over the foam up to the bevel. 3/8" is added to this pattern also. The center holes at top and bottom are punched in the top and tied to the foam/pan/seat back using the center holes in the seat back.....the remainder of the holes are traced onto the front by using the holes already punched in the back.. Not scientific, but it works.
Ratio of Lexol to water....mmm how do I say this...... some to a lot. In other words it isn't critical. Some Lexol to a lot of water. You'll know what is right when you feel how much easier your knife pulls through the leather when you tool.
Hope this helps.
Dave