it dosent really matter usually the second row are taller on my team our second row are between 5'5 and 5'8 but on teams we played they were over 6 feet tall height dosent matter though I am only about 5'2 and I play winger inside or outside center and also flanker depending on the day and I only weigh about 125 and I play high school girls varcity so age 13-19 and grade 9-5th year so that is about the same age group I anm 15 and grade 10

You'd have to be one of the tallest of the pack.

For u16s it honestly depends on the rest of the pack size, if you've got a fairly tall pack 6ft- 6ft 3 would be good for u16s If you havnt got a tall pack someone who's got a similar height to the other lock

At the pro level, I'd say 6ft 5 minimum, but at school boy level it doesn't really matter so long as you're not too short

theres not necessarily a certain size. You just need the other lock to be roughly the same size, and you just have to push.