The 2-DPMP (desoxypipradrol) he used as well as the EPH we are talking about here as part of your question... they are both DARI compounds meaning 'dopamine reuptake inhibitor', so they have similar action and should come fairly close even if the duration is very different.
It means that we should all take his information suggesting overstimulation, and take it seriously as something that is likely to happen with EPH as well. So better be careful, or even better skip it unless you have a good motivation for this combination - one that I don't (yet) see.
It was an easy call though: everything that I read about 5-MeO-DALT as well as the mere fact that it is a 5-MeO tryptamine makes one think that it is sensitive to causing overstimulation even on its own. Something like that does not tend to lend itself well to combining with even more stimulation. If the stimulation wasn't uncomfortable before, the combination should push it there.
Not saying that it is dangerous, but I personally would not be interested. If you are insistent on this even after checking with yourself to just be patient on some other compounds or better drugs to achieve what you are interested in... start off with the drug you want to enhance with the other one, and wait for it to plateau. Seems to me like this would be the 5-MeO-DALT.
Then carefully titrate the EPH. You may not want to snort it because that for sure will bring out overstimulating qualities. Unfortunately other RoAs are less immediate, so be patient working your way up. It's my bet that you will not have to use much at all to realize that this combination is not ideal.
Of course this is conjecture, speculation and prejudice otherwise I would not have mentioned trying it.