I always adjust from the non-drive side only, and this works fine. In fact, the cone and locknut on the freehub/wheel side are usually quite tightly installed to prevent removal from the axle, and I never take them off unless replacing a bent axle or pitted cone. The design of the axle/cone system allows complete adjustment from just one side. Simply install the drive side cone and locknut, cassette spacer and nut, and tighten quite hard. Then install the non-drive side cone and tighten until you have some resistance, spin the locknut down and then back the cone off 1/8 turn or so. There's always some stretch when the QR is fastened, so it needs to be just a tad looser than what you want it to be when installed. Ride it for a mile or so then remove and re-adjust, as the bearings will usually move all the excess grease out and need the play taken out again after a short ride under rider weight.