Good luck. Brohamer was a Sartin player and as such didn't have a lot of use for speed figs. At the time much of their work was done, Beyer figures weren't in the DRF. The DRF put out a fairly useless figure based on how the horse preformed to the track record for the distance & then another figure with the days average difference from the track record. It was compared to today's figures very inaccurate.
Creating pace figures is a bitch for a number of reasons. There is no prize for running the fastest 1st quarter or whatever, so jockeys try to run only as fast as they need to in order to keep their position. Horses of the same class have different running styles & abilities. The daily variant doesn't break down neatly into segments & using the entire variant tends to give you a wildly distorted number.
You have at your finger tips access to the DRF Moss pace figs, Timeform US pace figs & the Bris figs & Cramer figs. My advice is not to try to reinvent the wheel.