Do the players in the scrum have to remain in the same position ? If they are free to move then wouldn't it be effective to modify them depending on the situation. For example if you were 5m from the opposition try line and you wanted someone to power through tacklers but you don't have a big 8 you could use a ball carrying lock and shift the players around to compensate from the lack of power in the second row.Do the players in the scrum have to remain in the same position ? If they are free to move then wouldn't it be effective to modify them depending on the situation. For example if you were 5m from the opposition try line and you wanted someone to power through tacklers but you don't have a big 8 you could use a ball carrying lock and shift the players around to compensate from the lack of power in the second row.

Players can move around other than the front rowers. Players in the front row must be specialist props/hookers. It's common for the back rowers to alter position.

u could if u wanted to but most teams generally have a strong 8 man and u don't need to be big to power through tackles u just need to have speed behind u