Hello Paul,
Recoil springs are relatively inexpensive. Wolff, the standard in gunsprings, has the 1911 recoil springs priced at $7.89 each. The springs come in a resealable plastic bag with the spring weight on it. You should also install an extra-power firing pin spring (the FP springs come with some of the recoil springs)
Wolff also has sets of different-weight recoil springs with the FP springs so you can dial-in the recoil spring weight to the load you are using.
If the ejected cartidge case lands 3-6 feet away, then you have the right spring weight. If the case lands further away, you need a heavier weight spring. If the case doesn't get ejected from your gun, you may need a lighter weight spring.
FWIW, When I was shooting "softball" target loads (185 grain LSWC) in my Government Model, I used a 14 lb. recoil spring. Sixteen pounds is the factory standard spring weight, if you want to shoot 230 grain hardball.
Good luck, and let us know how it works out.
-Mk.IV
http://www.gunsprings.com/SemiAuto/ColtNF.html#1911Recoil