I've been using vrnecksafer before. Try this:
1. Turn off everything - DCS, WMR, SteamVR, Steam, vrnecksafer.
2. Start vrnecksafer, it should start automaticly WMR and Steam VR.
3. For center reset button in vrnecksafer use the same button you are using in DCS for the same functionaly.
4. In vrnecksafer under "Manual rotation" tab check "Accum"
5. Then start DCS.
Hope this will help