To Reply, I havn't put a turbo on a motorcycle engine, but I have done other engines. Current turbo project is on a jeep 2.5 liter inline 4 motor. And yes, these are all built by me. No kits.
Tapping into the high pressure side on the engine for supply line is perfectly ok. I have seen that location is on the right side of these little engines. People usually add a oil guage to this location.
As for return line, try to keep it short as possible, straight as possible, with little restriction back to the oil tank. The tapped in return line at the tank MUST be higher then the oil level at running condition. If you don't have it higher then the oil level, you will have some serious problems.
Also, you didn't post what type of turbo. Did you ever factor size of the unit to the amount of CFM the engine runs at? There is alot more to a turbo system then some may believe. (Yes, I have actually done calculations to size a turbo to a engine with required performance.)
Nevermind all I said: I clicked on the link. Put I do stand on my oil return guidelines.