Hi David,
I presume your treating this as a trig analysis, remember this is a cable, so like the letter ‘Y’, with g pulling straight down on the sled, your vectors will need to be adjusted by the Cos (Theta) of the angle, no?
I’ve not fully crawled through the spreadsheet just a quick look at some of the columns. It won’t purely behave as a pulley, however reasonably close enough for a model due to the cog/sprocket. I’ve also based this on the sled being perpendicular to the ground, and no black holes nearby, or large mountains ;-)!
The spreadsheet looks great, just got my sled cutting, so a few more calibration cuts and the fun begins.
Guy