Hifi Dave is the NAS & Lyra expert here as he's a dealer for both and has fitted many to each other. Not sure if he's away yet but a quick PM may catch him before his hols.
A call to NAS may also lead to some good advice, as if different counterweights are needed, they'd know who and why these are made and ordered.
In an ideal world, I understand that the counterweight should be kept as near to the pivots as possible. On my old Mentor arm, the brass main weight could be changed in its housing and I believe the current ones aren't so different.
Good luck anyway.
I can't go on and I can't go back, I don't feel so matter of fact,
I tried and tried to make good sense, What's the good to try it all again?