Add up the amps of your dash, headlights, markers and tail lights and that will tell you the amps you are dealing with.
Figure one 1157 tail light is 2 amps and you will be safe.
Brake lights and signals are on a different circuit, so those don't apply to your intended application.
(2 headlights on hi beam, two tail lights, possible front and side markers plus dash lighting)
A toggle on say 25 amps is going to get hot, so consider a relay that your toggle operates.
FYI, a fused 30 amp relay switched by your toggle should be plenty.
The amp rating of your toggle can be pretty low, like as low as a couple of amps, because all it will be doing is turning the relay on and off.
The relay will handle the load of the lights.
