One night in the past few days, the last after hours trade put clny up over 3% from that days close on 1,000 shares. Sometimes big percentage moves are on a last trade of 1 or 2 shares, an obvious case of painting. Neither means anything to the next morning's opening.
The only time after hours trading is likely to have an impact on (or indicator of) the next morning's open is a big percentage move on heavy volume which is usually the result of after-close news, like an earnings release.
After hours is a no-man's land where pros fish for suckers and they usually catch little ones. I've on occasion fished in after hours with a bid or ask on 5,000 shares trying to catch an adult fish. Much more often than not, if I get an execution at all, it's like 22 or 89 shares. It's been very rare for me to get one execution for all 5,000.