Before it starts to bleach the hair? I read 15 minutes but would like to go longer if possible

I do a quick dip and slosh, then rinse thoroughly!

I wonder how much it matters, understand the solution isn’t stable anyhow.

We let them soak over nite , rinsed, dried, finished no problems,

I've done like Newhouse with good results.

Thats what I wanted to hear. I need to be able to drop them in a bucket of solution, pop a lid on and head on down the road. My employer is squeamish about a scented truck.

Who knows what the pelts look like after tanning though....

The drug store peroxide in the brown bottle (3% peroxide) is not real strong. I am not sure that it would harm the pelt if left for a prolonged time. When you first put the stinky skunk in the solution, you get lots of bubbles as the peroxide reacts with the essence. When the bubbles stop, the peroxide has pretty much lost it's strength anyway. And when it loses the extra oxygen molecule, it is nothing but water.

If you are using a higher percentage peroxide like 40 Volume (12%) like beauticians use, prolonged exposure could affect the color.

I did mine over night too

If you add a little warm/hot tap water to weakened peroxide, it will pick up some oxygen from the water and start working again.
Sun light will kill peroxide, that is why it comes in colored bottles.

overnight never had a problem,

I am guessing this solution will work on leg holds also. I have two trap that got skunked this week