1) Unfortunately the custom class options for spell progression do not include a Warlock option. But you have some options. Option 1, on the character sheet select warlock as the class so it uses the spell mechanic. Then make changes to saves. In your subclass put the real classes name. Option 2, click the cog next to "spells" (Core, Bio, Spells, Cog). Then in Spell Slot modifiers put the correct spell slots per level. This will require updating every time the spell slots change. 2) Spell using the highest spell slot every time...based on your question I am assuming your group is using an Ammo/Spell tracker Mod? Otherwise you can just do it manually. If so, you will have to manually write out each spell in the spell list at the current spell slot level. Then redo that whenever the spell slots gain an increase in level. This is the only way to accomodate the ammo/spell tracker. If you are not using an ammo/spell tracker mod then you can simply rewrite the damage increases so they are always maxed out. Remove the upcast portion of the spell. Then manually remove the correct spell slot when you cast it.