What size crimp connector for 2.54mm headers?
I think you can use the below connector

http://uk.farnell.com/fci/65039-036lf/connector-receptacle-2-54mm-1way/dp/2112430

And for crimp

http://uk.farnell.com/fci/47745-001lf/crimp-socket-22-26awg/dp/1097977?MER=en-me-pd-r2-acce-con