New to me JD 790E LC; questions

I just signed the check today to purchase a 1994 John Deere 790E LC excavator. It has 3600 actual hours on it (meter works!) and is in good condition for being a 22 year old machine. Part of the package is a curved bottom trenching bucket with new rock bits. Its first project is to clear 100 acres of timber and replace big drain pipe in a flood retention dam. I have been running a borrowed Cat 315 which is too small and loose as a goose so a good tight machine is going to be a real treat. My plan after that is using it for land clearing and pond digging/cleanout along with my D6C and some sub work if it comes up. As of now it doesn't have a thumb and no auxiliary valve for a hydraulic but I haven't figured out how to use the one on the Cat as it is a pinned thumb and was in the way for tearing brushpiles apart. The questions I have are; 1) are there any problems to watch for on this model machine, and 2) what kind of hourly rate should I charge for a machine of this size? Trackhoes are a rarity around here and I think I can tap into a niche market with timber clearing and relatively (30') long reach pond cleanout. I have been performing custom older tractor and farm repair for the past 2 1/2 years and am excited about doing something other than just wrenching and dealing with the constant ****** of repair calls. I know machine operation comes with its own problems but with a service truck already outfitted, field repairs aren't a big problem other than the no pay downtime. It is to be delivered early next week and I'll post pics soon after I receive it.