Could anyone tell me the best way to set up the COG on this plane?

After reading the posts on the Zero I am setting the centre point on the bamboo spar ~45mm from LE. I have made up a crude balancing jig out of scrap balsa and have the plane sitting on a ~5mm edge. Does the part of the jig where it meets the bottom wing have to be less than this 5mm ? Does it need to be a 'point' like a pencil tip?

Also, I am having trouble balancing the plane. It seems that I can make it go either way, to tail or to nose. How are you supposed to balance it? Do you hold it horizontal in the jig and let go and continue moving the weight (in my case the batt) to and fro until it stays level?

Last question, the AUW I have measured is 16.6oz. I'm using the stock esp300c motor with kan1050 8 cell and stock prop and 20amp esc . With this gear and weight , what flight characteristics and flight times should I have? Gentle circuit flyer, Mildly fast acrobatic?

Any feedback greatly appreciated.

Thanks Raven.