To my knowledge, there is no way to get 2 bars at the same time, but you can quickly shuffle through the existing ones with 'R' and 'F'. I do the same thing you do, and split it up in schools of magic/categories, and I find that i works find with the hotkeys (although there is a bug where your chararacter, after a quick load, "forgots" the skills in a hotbar it hasn't "seen" yet, you switch to said hotbar and they magically apear in the skill tab again.)
However, there is a mod that changes how items are added to the hotbar, making it less, well, everything. Could look into that.
Last edited by Elidan; 23/09/17 09:49 AM. Reason: typos