School specialization and the Ultimate Magus?

[Mercurial891]

“ Spells of the prohibited school or schools are not available to the wizard, and she can’t even cast such spells from scrolls or fire them from wands. She may not change either her specialization or her prohibited schools later.”

So if I have a Red Wizard Diviner who sacrificed Illusion and Enchantment, but becomes an Ultimate Magus and Beguiler, what happens? Is this combo even possible?

[Tzardok]

The description of specialization should be read as "can't cast those spells through being a wizard". It has no influence on what you can do through other classes.

[Ramza00]

This is one of those things that you should come to an agreement with your DM before doing.

Rules as Written you can use those spells on the spontaneous side, as well as use magic items without umd. Some DMs may not like it but I argue this is fair and semi balanced for no matter what you make your main caster level one level behind and thus delay the save dcs and other boosts since d20 assumes you advance your primary ability ever 2 levels. Likewise your secondary ability is 4 levels behind and thus is 2 save dcs behind but also all the other benefits caused lower level access to a specific ability like flight vs levitation or short range teleport to long range different city teleport etc.

And the previous sentence is the best case scenario if we are not using fast advanced prcs. Of course traditional UM is designed to rob you of the best case scenario but you can use tricks to counter it.