Haven't tried it -- yet, but Profili 2 might be an answer.
The website says it will do what you're looking for:
http://www.profili2.com/eng/pannelli_pol.htm
OOPS _ SORRY 'Bout that - seems that Profili won't generate Gcode - or doesn't seem too. (Had to have a load and look)
SO, maybe try JediCut - it even mentions synch-points -
http://www.aeropassion.net/index-en.php
Are you planning on the wing being cut from a single blank - or several and thats why you are looking for "sync points?"
I think most wing software would let you cut the spar location on a taper just like the planform. Seems a bit unusual though - most typically the spar is at the aerodynamic center for the entire span -- unless you have a very unusual tip profile.
Jim
Hugo - had a bit of a play with both and maybe the one you're looking for might be this one:
http://www.excelcut.netmyne.com/ Its free too! Seems you'll need an older version of Excel - He wrote this in excell/office 2003 I recall.
Profili2 won't let you export GCode, JediCut is awkward for me - not french reading to well, ExcelCut will now import a dat file - so you can get to that quickly from the various databases. And the spar can be placed as you want. Best of Luck - Jim