First off the spansule are extended release, not very good for recreational purpose. You might wanna crush the beads carefully to a fine powder.
Since you never tried amphetamine I'd suggest to try 5mg first, see what happens, you shouldn't feel much, just more awake maybe. If on the other hand you feel shaky and uncomfortable, racing heart, anxiety, amps are not for you.
If the 5mg test is ok, 20mg crushed and dissolved in water with no tolerance should bring you to a nice place, but don't expect anything like MDMA. Also it's possible that if you usef MDMA frequently you'll feel more stimulation than euphoria.
I'd strongly suggest not to go over 40mg in one session, or you are in for insomnia, racing heart, anxiety and other unpleasant side effects.