I never did the tibialis raises consistently honestly.
As for progression, first I focused on getting to 100 in as few sets as possible. So at first I was doing like 25 reps max and after a while I could do all 100 based on tempo (usually more like 70). When it gets really easy, I'll either pick up some light weight (like 10 or 25lb) or focus on getting MORE out of each rep - for example, doing the negative portion slowly. Do them close to something I can use to push myself down for the negative... stop in the middle of the rep (pause), go back up slightly, go back down... do a bunch of partials... you get the idea. Some days I would go up to like 200 reps, although most days usually were around 100 just because it's easier to do consistently.
I think I'll start doing the tibialis raises again.