I had my LGS smith do the springs on my New Model 66. The first attempt was almost 1911 light, and it wouldn't ignite hard primers. Went up to the next power Wolf spring and a 14lb rebound spring and it's 100% reliable, and a good bit lighter than my Performance Center guns. Luckily, the trigger was already smooth (but about 14 pounds, hence the change), so I didn't have to pay for a trigger job.
If your trigger is already smooth but just heavy, IM(limited)E the springs alone should do the trick. If the trigger is gritty or stacks, you'll still need a trigger job.