Steps:
1) Decide what is important to my actual game.
2) Dispense or adapt whichever is easier to adapt of 3.5 rules and the supplement in question.
No, I'm not just being snarky.
As another general note, it seems that if you want to make your classes with caster levels and other class abilities (like True Necromancer and Spellsword) to compare with the classes in the DMG, you would have to be a lot more generous with the class levels. My guess would be to accelerate the spellcaster levels by 50%. This does not apply to arcane trickster, who already seems to be written to this philosophy.