Can stackable Arduino headers be automatically soldered? I want to design an Arduino shield with stackable headers, so it will allow other shields to be mounted on top of it.



I was wondering if these could be soldered automatically. Neither wave nor reflow soldering seems to be an option. Wave soldering would leave solder on the pins so they won't fit in sockets, and for reflow (pin-in-paste) the long pins will completely pull the paste from the holes. 
Is hand-soldering the only way (making the board more expensive), or is there still another way? Would it be a good idea to supply the shield with the headers not mounted to save cost?
Or shouldn't I assume the average Arduino user has a soldering iron?
I would suggest using SMD headers on one side and through hole on the other side. One side with this: http://www.tracepartsonline.net/(S(30y0dp21y1rd0u3erv1mrrbw))/partdetails.aspx?Class=ASSMANN&amp;ClsID=/F_ASSMANN/ASSMANN.010/ASSMANN.010.170/&amp;PartID=10-18062010-079808
and one side with this: http://www.tracepartsonline.net/(S(30y0dp21y1rd0u3erv1mrrbw))/PartDetails.aspx?Class=ASSMANN&amp;clsid=/F_ASSMANN/ASSMANN.010/ASSMANN.010.170/&amp;ManID=ASSMANN&amp;PartFamilyID=10-23062010-067691&amp;PartID=10-23062010-067691&amp;SrchRsltId=1&amp;SrchRsltType=0

You will shift upper side a few mm from bottom side, and use glue to have upper side set in place and then reflow for soldering on both sides.