Well a long time ago when I was in automotive tech school. We were instructed to never go more than :10 seconds at any one time. I always did the Mississippi 1, Mississippi 2 thing, to not over due it. Then always gave it a 10 sec. rest.
I will say this though after about 3 tries I would usually start looking for the problem.
About tech school... that was back in 78-79 and I found out I didn't like working and getting greasy on other peoples cars so instead I went into parts counter work at dealerships for 6 years. In 84 I got out of cars altogether, I just recently jumped back in. Back in '99 I acquired a '69 Camaro. Sold it and now i'm here with my first love a 77 swb that I've been tinkering around with. Been having a lot of fun with it.
God Bless,
Terry
should of been 76-77