Help with Muncie speedo gears

[SS427]

As many may know, our 69 Chevelle when found was missing the M21 so I took one off the shelf that I had (originally came out of a Pontiac) and rebuilt it using the correct Chevelle tailhousing. What I am not sure about is what speedometer drive and driven gear I need for the 4.10 with F70x15 tires. From talking with Eric at Crash Enterprises we came up with a small 8 tooth metal drive gear and a large yellow 24 tooth driven gear when used in conjunction with the .7333 speedo reducer. Can anyone else concur with this information before I put it all back together or offer other insight? I also could use part numbers if you have them.

Another question, does the 69 4.10 car use the offset BW rectangular adapter or the round 90* adapter? Thanks in advance for your help.
Rick