I own an 1985 DG-300 3e127 with 1350 hrs. I too have a sizeable gap
between the wings and fuse (~1/8") after assembly. However, my wings
have virtually no freeplay or movement at the tips. The maintenance
manual does call for installing shim washers on the pin(s) when there
is freeplay (sec 1.10). With the amount of motion you describe I would
get it looked at. After consulting with your local A&I you could
contact DG's service dept via email for washers (and/or specifications
on max allowable freeplay). They have always been very helpful for me.

John Cotter (XJ)