911 SC Front Trunk Drainage w/HVAC Delete

[t-cup]

After lurking here for over 1 year, I've found a question that exceeds my ability to search.

I've recently removed the HVAC system from my SC, and gave all parts to a friend. Unfortunately, one of those parts enabled drainage from the vent on the cowl through the trunk just behind the smuggler's box. Said friend has agreed to purchase whatever I need; now I've just got to get a part number.

Has anyone got an idea what sort of lightweight plastic bit might fit there?

Thanks in advance, this forum is at least half the fun of owning the car! And, yes, I realize there's a bit more work to do in tidying up...If anyone's got advice on pulling out all the disused wires, I'm all ears.