That 40 deg must be on another motor, not the 2100. I think he's in the right ballpark with the 23.6 . The dish elevation isn't related to his latitude {other than that declination is related to latitude}, it's related to the angle on the motor and to his declination. If I remember right, with the 2100, it should be 30-declination, and his declination south, is something like 6.2, so 30-6.2 is around 23.8. Although I think he'd be better off starting with using a declination of 5.6, he can't do that unless he starts off with a motor elevation of 49.4 instead of 50. But anyway, I think his 23.6 is close enough as a starting point. But with the inaccuracy of these dish mount scales, he'll have to search quite a range around that. But not up to 40, more likely down to 20.
When I did this on my new dish, I used my little hand held meter, and never even tried to set this dish elevation accurately, but did try to set the motor elevation accurately. Then, I loosened the dish mount bolts, and moved that thing up and down, while
aiming south, until the meter squealed. My meter actually worked pretty well with the small dish, it actually gave as much signal as with my big dish I think. I was surprised, as I was half expecting only to be able to find DBS sats, but it found linear sats easily. I'm back to liking the little meter. Of course, the first try, I found the wrong sat, but once I figured out what sat I found, it only took a few minutes to find the right sat.