It doesn't take too long at all really, the longest part of the whole danged process is the crimp, but when you are doing 20 or so it doesn't take too long.
The shelf life is not too long however- they tend to get shot pretty quick!!
I would say about 30 to 45 seconds max if the case is already cut and trimmed.
I do my low pressure smokeless loads much the same most of the time as well, except I often use a modern wad instead of the stacked fibre wads.
I also often use a Harrel measure to charge the cases when i am doing 50 or more.
if you do 50 one step at a time it cuts down the overall time as well.
Cat