I would suggest the last few PC ties be soldered ONLY on one side. Once your track is laid in place and the easement is gently formed - then solder the other side and set the wooden ties. Having all the PC ties soldered and trying to form the easement would create kinks and tend to twist the rails.
-ed-
_________________
-ed mccamey-
COSLAR RR -
http://www.coslar.us/NMRA Standards and Conformance Department
PROTO & FINE Scale Coordinator
I estimate I have about 5 pounds of coupler springs somewhere in the vicinity of my workbench.