In searching around for information on the F-4 Peace Jack project, water injection in mentioned as a key, amongst other changes, to getting the Phantom to Mach 3+.
But it took two 2500 gallon water tanks.
So the questions are this: how long would that volume of water last? Were there significant design changes to materials within the engine to tolerate the different mixture's behavior? Could, in theory, water injection be carried along, say with a bit of MeOH or EtOH to prevent freezing at altitude, for short 5-10 minutes of high speed either over target or as an escape from danger.
I'm not, however, asking about shape revisions for the intakes as my modeling skills aren't advanced to that level yet.
Yes, these questions partain to both the Draken and Phantom projects at hand.