GO FOR IT, NEWBIE!!!

It's a bit complicated and not very logical according to the current rules – spell scrolls of levels 4 and 5 CAN be used after capturing a suitable Pandora, BUT only if the starting Castle does not have a Guild of Mages (GM) of the required level. For simplicity, I would remove the highlighted letter from the following rule:

"5.8. It is forbidden to use spell scrolls of levels 4 and 5 without building the corresponding level of the Guild of Mages (GM) in any of your Castles. If the starting Castle does not have the corresponding level of GM, then you must comply with subparagraphs a, c of paragraph 5.2."

Even better would be to not use the reference at all and write it like this:

"5.8. It is forbidden to use spell scrolls of levels 4 and 5 without building the corresponding level of the Guild of Mages (GM) in any of your Castles. If the starting Castle does not have the corresponding level of GM, then you must fully build GMs of all levels in any two Castles that you own. Or capture an opponent's Castle with the required GM already built (it doesn't matter how long the captured Castle remains under your control). It is not necessary to visit this Castle with a hero."