hi
as for the weight for balsa as some one in this tread say ..its a big diffrence ...I got some balsa from a local store in norway that I heard has good balsa ,  it weight was from 15 gr to almost 30 for 1,5 mm even the 15 gr is at the heavy side I got some from Heerdegen down to 12-13 gr 10 x 100 cm x 1,5 mm and all the sheets was within 2- 3 gr from that ...hugh diffrence to this other stuff....