Yes, Walter's doc is very good to go by. Your 2.5m tree might look O.K. if you have it 2m off the ground. Just a thought. And another thought, 12 strings double to 24 2.5m? Just don't plan to add on later. Pixels seem to very enough to cause complaints. So if you want more later, buy them all together and plan on using these for another project. I'm sure you'll love what ever options you pick. Just let us see it. Thank's!
Brian
Brian