I would only use the chains on the main movements. I don't use a percentage of chains (they normally come in 20-25lbs increments per side, so kinda hard to use a precise percentage when the weight gpes up in 40-50lbs increments). I normally go with:
No chain if your max on a lift is less than 225
1 chain if it is between 225 and 315
2 chains if it is between 315 and 405
3 chains if it is above 405
It's not set in stone as I might sometimes as as much as 5 chains per side. But that is a good starting point.