I found this question very instructive, as paying attention to the score is all-important.
Calling next from 1st seat without any trump seems suicidal. But I ran this scenario through my euchre program and discovered that, despite being euchred 62% of the time, calling trump is still better than passing, which results in losing points (and thus the game) 68% of the time. Thus, calling next as trump is the lesser of two evils.
I also found that leading the AS is about 2% better than leading the 10C [that's inconclusive in my mind, given the possible inaccuracy of my program, so I'm happy with the stated best play].
Note that passing is a much better option if the score is not a factor!