Merlins Magic Sleepsuit

Jessyka
Has anyone tried the MMSS and failed then tried later and it worked? If so how old was baby and what weight/height? Specifically with an Exclusively breastfed baby...
My guy is 9 weeks and 12 lbs which is the minimum weight and he actually slept worse. I don't know if I should try more nights or wait a few weeks and try again? 
He normally sleeps 2-3 hr stretches and last night it was 1-2 😳
I know the recommended age to start is 3 months so maybe I'm trying too young? I just see these people that started st like 6 weeks with success lol.
TIA