What are the exact dimensions of the 20ml and the 30ml vial: diameter and height?

I do no know, I purchased the 10ml vials. It says 50 x 22 mm on the box.

Does the rubber seal on the inside of the vial have a small gap in the rubber to allow all of the med to be drawn up, or is it continuous on inside?

I've never seen what you mention. The rubber is a one piece seal with no holes. When you insert a syringe into it, it makes a hole, however, it seals up (this is the self healing feature they're talking about). So you tear the plastic cap off permanently, which exposes the rubber seal. It seals up so tight, that the contents can not escape even when upside down.

ASIN	B09B7SSQ1L
Best Sellers Rank	#27,437 in Beauty ( See Top 100 in Beauty ) #7 in Nail Tool Sterilizers
Item model number	KSUS-SEV-M
Manufacturer	Ks-Tek
Package Dimensions	14.2 x 11.51 x 2.39 cm; 82 g

KsTek Sterile Empty Vials with Self Healing Injection Port,with Flip Off Aluminum Cap,Sterile Package (3ml,10) 3Ml

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