Is your Damascus Grand a vibrating shuttle/bobbin machine, or a rotary machine. I think it's a rotary if it's like mine.
[ATTACH=CONFIG]475231[/ATTACH] If so, the problem won't be which needle size to choose for what you're sewing, but rather can you find ANY needles that will fit that machine. If it's vibrating shuttle, it uses 20x1 or Free BB. I think, I have to go check, again to be sure, but I think we're talking Boye #21 or Free DD1221. We have a couple gurus here who will have the answer at the top of the head, rather than lost in the fog...