This is a 90" wingspan EPO model glider, did originally have a motor, but i removed it so it is a proper glider. Proper glider?
How much wind is enough to fly a glider this size in ??
Have you flown a sailplane yet at all? Are you slope soaring? or high starting?
Is it best to be high ?? Height is a what you want to achive, You want to stay up in thermals as long as you can, which will usually result in good altitude.
Is it best to be nose heavy, or tail heavy, or PERFECT for a glider ??
You need to determine what the CG is. I would for starts, balance at 40% of your wing chord, then work it forward from that until you are comfortable with the balance and handling.
If you have never flown a RC sailplane before, I would reccomend you start out with a smaller one and a durable one first. Or, have a instructor with you using your ASK 21.