Got through Lasciate and through I'd Rather Be Surfing to the Suffocation Room on I'm With Surfing with no further hits taken.
The Red Cloak doubles everything else's speed (game clock being the relevant thing here) so minutes go by in thirty seconds...but it still takes a real minute to generate ammo, so that limits ammo generation a bit (my main enemy is running out of bullets). Also, resting still takes the standard se7en minutes but heals you for half as much; se7en resting sessions is I think normal to regenerate but it took me thirteen.
Healing is more esthetically pleasing than running around at 0.5 health (of 20 by this point, could be higher if I were playing normally) but I have to poison myself next level so it won't last.
If it is true that there are two hours of air you could conceivably not put the cloak on until an hour in, using one hour for the first hour and one for hours 2-3. I might run a few test scenarios once I'm through.
Basilisk is cheerfully chugging away in the background now (11:20 AM on Sunday; I'm to get out at 11:57-58) and I'm making frag grenades for the Ghast and the Furious to come...
but I found something you can put in the Cedar Box that I wouldn't have suspected...