It depends on how many other responsibilities you have or other activities you engage in, and how much you care about the project, I suppose. To me 10 hours of solid study after work is a lot, but other people might throw out some other stuff I do and be willing to spend it studying. I can’t comment on whether it’s a good idea. (I believe there is very much such a thing as too much work ethic).

For us studying physics, thats like 30 hours of actually attending class for each course, so 90 total, then some days of study, say 3 x 8h, thats more like 114h, not 300...