Your best bet is to find a similar sized pattern that has those sleeves, and follow its shaping directions for the armholes and sleeve caps. It's not easy to guess at armhole shaping, because the armhole and sleeve cap have to be just the right size to fit together.
Hope that helps.
KnittingHelp Queen Bee
“It is not because things are so difficult that we do not dare; it is because we do not dare that they are difficult.”