This is a tactic I've been using on my Football Manager 2018 save for 4/5 seasons.
First season at West ham I didn't use it at all, so I had no instant success. I won the Premier League on the 4th season.
Moved to Bayern in the 5th season and the amount of goals I scored in one season is ridiculous (see below).
I'm not sure if it's overpowered or if it's just the fact that I had the right players. To be fair, Bayern is full of top quality players though.
If you test this tactic, please let me know in the comments if it works for you or not.
I'd rarely use OI, and if I do it'd be if the team seems to be struggling; I'd let the assistant do them.
This tactic requires a team with a decent work rate, 12+ is recommended. When in big games or playing against 2 strikers I'd change from slightly higher to deeper.
If I've missed anything let me know and i'll try get back to you!