CIG has released a new page that’s basically a tutorial for Medical Gameplay. In the info is a section for Medgel which specifies the capacity of the different medical bed tiers:

Each tier of medical bed has a different MedGel capacity.

  • T3 MedBeds can hold 100 cSCU of MedGel.
  • T2 MedBeds can hold 200 cSCU of MedGel.
  • T1 MedBeds can hold 400 cSCU of MedGel.

As well as the respawn distance of the different medical beds:

MedBed Tier Regeneration Cost Regeneration Range
Tier 3 100 cSCU MedGel Within 50,000 meters of bed, enough to cover most gameplay areas.
Tier 2 100 cSCU MedGel Within 8,000,000 meters of bed, enough to cover most planetary bodies.
Tier 1 100 cSCU MedGel Within 150,000,000 meters of bed, enough to cover most star systems.

There’s also a slideshow of different medical ships and the different tier medical bed configurations that they can have.