OPPS ,After looking the plane over I did use the 8-18 lb 700 series robarts. The spring air do have a slight prob if you store the wing with the gear up, you will need to keep air on the system. After looking at the Lado site, they have come down in price alot seems like when I looked before they was close to 400 bucks for a set for the mustang W/O struts.
Yellow air is another good source for retracts and although there air they work and act realistic.
Don't forget to get the correct tires since your going all out on the gear. BTW when you get the gear doors figured out lets us know how you did it ok *S*