you know what your right the higher the dose the better the strength and the less pump.The pumps seem to vary by user more than any other aspect of the formula. The euphoric feeling/alpha mood you describe is something I notice myself and to me it is the second best aspect of the formula behind the focus/mind-muscle connection.
Go ahead an try two caps. I promise your muscles won't explode!
For me, the effects of Uncut last for 4-6 hours just depending on what I am doing. I have used it for evening workouts myself and I follow a very similar schedule to you. I get off at 5:00, so I take my Uncut (2 caps instead of my normal 3) around 4:00 and head to the gym a little after 5:00. I usually got to sleep between 9:00-10:00 and haven't had any issues yet.
That's me though. I have read some feedback from other users that did have trouble falling asleep after taking Uncut, so you might just want to start with 1 cap and work your way up.