Retained sole - comfort question


Toons has super deep collateral Sulci in both hinds. His fronts shed some sole to create cuppiness, but his hinds are not showing any signs of shedding. I usually easyboot glove him when I ride.

1) How does one know if it’s retained sole or just a nice healthy thick sole? 

2) Would pads put too much pressure on the soles if retained sole or are they indicated if retained sole?

Thanks so much,
Robyn & Toons 

North Bay, CA, April 2016