After 100 I believe 10 min is fine.
Even if you only play 2 hours a day, you will get to 120 in a fair time.
With 13 gains a day, it will take you 16 days to get from 100 to 120, that's not bad.
If you never sleep, you can do it in 4 days.
When I got my powerscrolls for archery, anatomy, tactics and healing, I did not think about when to gain, I just played the game. Only thing I had to care about was to find right level of mobs/players to get my gain.
I did not feel it hard, even when it was 15 min.
When you get to 100, you can PvP. If you want to end up with 6x120, you can take skills like hiding to 70 and drop them when you need the points. There are some skills nice for a newbie, that can be dropped later.