They look nice, I would use a bit of a smaller cord ( not too small though ) but to make the chucks heavier - you have a couple of options
-You could drill a couple screws in the bottom, or some nails. You have to be careful not to split the wood however.
-You could paint the chucks (You would be surprised at how much difference in weight a pair of painted chucks and a pair of bare chucks can be)
-You could use tape or tennis racket grip to add some grips to the chucks, which also add signidicant weight.
-Or, if you looking for a much more significant weight, try making some oak chucks. The ones I made are pretty heavy.
Good Lucks, and nice first DIYs !
