Here's what I did:
1. buy inscription to 40 in New Haven
2. make poison scrolls to 45
3. sell all poison scrolls back to NPC
4. make recall scrolls to 50+
5. keep or sell recall scrolls as you wish
6. make spellbooks until you are gm or bored. (you'll need lots of scrolls. I found a fel mage shop where faction prices had scrolls set lower than normal price, bought full stock, wait for re-stock, repeat)
I actually ended up just using ggs on lvl 8 scrolls to get the last couple points.
This is not the optimal guide in terms of price as each spellbook requires 10 scrolls...and if you actually scribe mage scrolls you can sell them back for a profit. It was fast and did not require mana regeneration though. I sorted through the ones I made and kept at least one of each slayer book that was created. I dropped the higher intensity LRC, MR, or LMC as well as unneeded slayer books in New Haven in case someone wanted them. The rest went in the trash, but you could turn them into the Brit library.