oooh! Great adventure :)
You've read the chapter in the appendix on converting adventures right? The main thrust (as you've rightly surmised) is to retain your agenda, but be inspired by the situations, setting and dangers of the module. You are effectively focusing your options on a hard / soft move (and scene framing) to the prep at hand.
So have the wizard as presented! If he's the 'signature' monster of the adventure, what's his instinct? What does he want? Freedom, yes? So write a couple of impending dooms that will come to pass as the adventurers do nothing to change his situation - one of the most effective ways to do this (I've found) is to re-incorporate info revealed during chargen and bond-writing into these portents and/or have other factions in the dungeon interact with the wizard according to their instincts given the players actions.
You could even frontload the session as you start in a tense situation, write an Adventure move such as the one on p.352 and tie the results back to knowledge / leverage on the wizard.
Heck, why not just open the game THERE - in a tense situation with the wizard, they have found him and he offers them something far more beguiling than just gold (look to their character sheets and bonds) to set him free. Combine this with an impending doom of another danger in the dungeon and you have time pressure added to the mix.
I mean this is ripe for getting the players to
discern and
spout lore, introducing new and exciting details to your dungeon world about the wizard and his history. All you come to the table with is that he is powerful, he is trapped by his own foolishness and that he wants out big-time.
In regards to your poison custom move... I like it! Not too harsh at all, it is poison after all... There was an old 'saving throw' move from an earlier edition you might like to resurrect / modify? How about:
Make a Saving Throw (Con)
When something inflicts an effect (magic, poison, calamity) upon you, roll+Con. On a 10+, nothing else bad happens.
On a 7-9 the GM chooses one.
On a 6- the GM chooses two.
• You drop something valuable
• You break something mundane
• You miss something important
• You lose your footing
• You lose track of someone or something
• It’s worse than it seemed—take 1d10 damage(ap)
Which really is just a 'softened' version of your move :)
I'd just add a few of the above choices to your iteration and write it up like so:
Make a Poison Saving Throw (Con)
When deadly poison inflicts its effect upon you, roll+Con.
On a 13+, you feel a shooting pain, but the venom has no other lasting effect.
On a 10-12 the GM chooses one and you choose one.
On a 7-9 the GM chooses two and you choose one.
• You drop something valuable
• You break something mundane
• You miss something important
• You lose your footing
• You lose track of someone or something
• It’s worse than it seemed—take a debility
On a miss,
Last Breath Sucker.