I would not be snipping any strands off. Nor would I ever use Wire Nuts to make any connection in a moving vehicle.
The proper way to handle this is to either use a wire lug with the right size hole... Or...Make some up using Copper Tubing . You could also use washers ,but make sure that You tighten the Lug Nuts and use lock washers or Use locking nuts.
To make wire lugs using Copper Tubing :
Cut a length of copper Tubing two and a half to three times the length of the stripped wire end.
Using a Vice squeeze one end of this tube flat . Drill the correct size hole through the flattened end to attach it to the lug. Grind the flattened end to round it off or remove sharp corners.
Slip the tubing onto the stripped wire and secure it using a centre punch to crimp and Solder .
I would use coloured Shrink Wrap to seal the job!
