Cryotube mechanics are interesting, they inject chemicals about once every 34 seconds, and inject a total of 10 units split among the ratio of chemicals in the container, so for example the cryoxadone accounts for 0.8 parts of the whole container, so the cryo tube would inject 8 units of cryoxadone into the patient. Now, cryoxadone has a metabolism rate of 0.4 units per cycle (a chemical cycle being around 2 seconds), so by the power of maths this means that you'd have 1.2 units of excess cryoxadone in the patient by 34 seconds which means you could lower the ratio of cryoxadone in your mix. This isn't much but considering the other chemicals in the mix, only 1 unit of each would be injected every 34 seconds which isn't really long enough to do anything useful.
Personally, I'd pick epinephrine over ephedrine due to the fact it has a lower metabolism rate, no addiction chance, is better at healing oxygen damage, and will help people with cardiac failure. I may also put some perfluorodecalin in the mix too sometimes, only downside would be the addiction chance in this case. I find mito to be overrated in cryo mixes, and is probably better replaced by something that'll just heal external damage instead. My reason for this is that not many people are going to have so much organ damage that it's going to cause them to be unstable and actually kill them. In the case of a heart attack, epinephrine will help prevent that in the first place and therefore prevent the oncoming brain damage.