Hello,

I am trying to create a "Third-caster Warlock," that is, a warlock with both Pact Casting as well as the Eldritch Knight-style thirdcaster slots. However, following the guide on creating homebrew thirdcasters (https://www.dndbeyond.com/forums/dungeons-dragons-discussion/homebrew-house-rules/119032-how-to-add-spellcasting-to-subclasses-for) results in a warlock with its normal pact casting slots, plus a second set of pact casting slots with the same progression as the normal warlock slots except they only reset on a long rest. Which is not quite what I'm looking for.

Is there any way to work around this?

Nope. There is no way to make a Warlock subclass with functional ⅓ Spellcasting. I first tried it 3 years ago, and have periodically tried it since to no avail.

Unfortunate.

I guess my workaround is going to have to be coding a bunch of extra "actions" that just track how many long-rest spell slots you're going to have at any given level.

Figured out a workaround.

Not exactly convenient to use compared to just pushing a button on the Spellcasting page, but it works.

Not bad.