Can't tell subscribers as that is only what is announced being approx 1,000 subs at last known number.
The most recent tournament would of been 120+ people
https://mogul.gg/tournaments/details/42889/pubg-qualify-week-2-premium-member/
Reason I say + is some teams might have subs in case people aren't able to make it or for strategic reasons, one player might be more aggressive or defence which the team might want. For example SK Telecom is a pro team within League of Legends which is a 5v5 game yet they have a roster of 9 players.
Certainly wouldn't expect the teams on Mogul to have that many extra players but there is also nothing worse than forfeiting a game because you couldn't fill the team - happened IRL when I was a kid doing sport and have seen it happen when I played video games too.
