Tom,
I've rebuilt a couple of 3-rotor engines (one is flying). The real difference is the 2-piece crankshaft. You'll need to beg/borrow/steal a crankshaft splitter before you can dis-assemble the engine. The front rotor rides on the short shaft. You'll need to remove the front rotor first, then separate the shaft halfs, then you can remove the #3 and finally #2 rotors.
You'll also need a way to remove the "big nut" from the flywheel end of the engine and a puller to get it off the crank. A thick piece of steel, drilled to match the flywheel bolts worked for me.