I have yet to encounter a problem mounting a 2-stroke inverted. Following the common-sense related rules such as removing any fuel line issues is a must regardless of engine orientation. A tip that saves some of the flooding issues is making sure the throttle is completely closed when the engine is not running. Often, little priming is necessary. Bench running an engine inverted for initial set-up is a wise decision. If you cannot mount the engine inverted in your test stand try rotating the entire stand while the engine is running (I have a stand-alone test stand so this is not difficult for me).
The fuel tubing that comes with a new tank is of the 'thin-wall' type. Often, with smallish tanks, say up to around 12 oz., regular fuel tubing will not work effectively when used as a clunk line due to its rigidity.
An easy way to secure fuel lines to nipples, clunks, etcetera, is to simply cut a piece of regular fuel tubing about an 1/8" (3mm) long and gently push it over the end of closed forceps or needle nose pliers. Carefully open the implement's jaws enough to gently nudge the end of the fuel tubing you wish to secure inside the open jaws. Pull the thin piece of tubing off the jaws and onto the fuel line. Attach line and push the sleeve into a position such that it secures the fuel line onto fitting. I don't have any pics with me but it works great and is... FREE.