2 suggestions
1) don't make your ground hidden like that, run your ground (10 ga) directly from the existing grounding point on the frame where the battery attaches to, this provides better access to cleaning the connection point, and prevents ground loop issues. The ground is as important as the hot wire.
Remote grounds often have issues in continuity.
2) make sure you have an inline fuse on the hot lead, preferrably as close to the batt as possible, 30-35 amp should do it, and again 10 ga wire.
Half the issues on adding in hot points comes from lack of easy access to the connections, and in an emergency you may need that to disconnect fast, if something goes wonky...
Jmho.