The standard side stand on my 1976 Ty175 is 348 mm from the center of the mounting hole to the very tip end.
That being said, I find that it is too short and the bike leans over too much. This puts a lot of weight on the stand and if the dirt is soft, the bike will fall over.
Being in the states, I buy 5/8" solid steel bar stock and cut a piece 50mm long.
I cut the stand where it is approximately 5/8" in diameter and weld the bar stock between the two pieces.
The stand is then 398 mm long from the tip to the center of the mounting hole.
The bike still leans over, but stands up straighter and doesn't fall over as easily.