Fiberglass resin to hardner ratio

I had a deer hit my 72 on front passenger fender, 

the mix ratio says 2% hardener, is there a rule of thumb , like 2 drops to a golf all size resin?

2% seems hard to guage

thanks 

Just looked at my can of Bondo and it says to mix the half ounce of activator to the 16 oz can of resin. Obviously you wouldn't want to mix up that much at one time but that should give you the ratio that you're looking for for that particular brand. 

That's a good gauge , I can divide it for smaller.

thank you 

That's a good gauge , I can divide it for smaller.

thank you