Hi G Dog, I never seem to have a problem removing screws because I don't torque them in hard. Complete screw sets can be purchased for ~$25. Also, an 1851 screw set works for most of any same manufacturer's 1860 screw needs.
The secret to not buggering screws is to use a good screwdriver bit set. Of course, there is the occasional slip, but having extra screws on hand seems to minimize those occurrences, a Murphy Law thing.
Regards,
Richard