Known Grimoires - possible house rule

[Darkson (Simon)]

Possible House Rule for any future campaign(s).

If you find a Grimoire for a spell the wizard already knows, you have two options:
1. Trade in for 200gcs as per the rules.
2. In the post-game you may improve that spell by 1 (costing a level as normal). You may not improve the same spell twice in a post-game. Grimoire is destroyed.