Don't sell yourself short. The average labor rate for most parts of the country are $85-150/hour.the shop down the road that i have a good relationship with is 50. and they love me because I work on the junk they don't want to work on. My overhead is only about 1000 a month with everything, and i still seem to struggle,but were getting by, Figured id try to suck some info from the limitless internet.
And i'll definitely look into some warranty labor books