It is largely SM preference, however the way I run it is we start about 3 to 4 lines before a cue sequence, and we work until a line or so after, then I call stop. Over cans I do a check with all involved parties that the cue worked fine, then I call out the next start position.
There are 3 main things that contribute to a well run "wet" tech, I believe - they are that:
a) you keep things moving. If fixing a problem (ie with desk programming) will take over 3 minutes, that is too long, and should be noted and fixed at a later time (without actors). Exceptions being dangerous problems.
b) you do not keep repeating one sequence over and over again. Run it the first time, if there is a problem, see if it was just a case of lack of attention or something - if so, you can either move on or re-run it, if it is a more complex problem (hard sequence etc) slow it down, run through it at the slow pace, then re-run at speed. If there are still problems, note it and fix at a later time (without actors)
c) you must communicate commands sucsinctly - don't blabber on, during tech, be all business. Do not tollerate actors talking, do not accept people not paying attention, and most of all, do not allow the director to hijack.
My cues are drawn up something like this:
+------+
| LX15 | script->>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
+------+------------^
| SD03 |
+------+
SB LX15-20 script->>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
----------------------^
basically, GO's are written in a box, either above or below the line into the script, SB's are prefixed with SB and have no box.
Standard calling tends to be something along the lines of this:
SM: Stand by LX 15
LX: Standing by
SM: LX 15 .... Go!
I like to leave at least 3 decent length beats between a standby and a go - however it all depends on how much time is needed - deck crew may need a minute, Fly's 15 seconds, LX, 1 second. Your ops will tell you if SB's are too short, or too long.