Got mine stripped at 38weeks and i was 3cm. Got the second strip at 39weeks and was still 3cm. Went into labor 9hrs later and 24hrs after the second strip i was holding my daughter.
I got mine stripped with my first one and i became more dilated I was 1cm and went to 3cm the next visit and they said I could have the baby if I wanted to, so then I was induced and went through 27 hrs of labor. Everyone's different though I heard of it doing nothing to some people and others went into labor only hrs later.
It could be hours, days...you never really know. It's different for everyone.