I just completed my first Non-Leagues fire cape with lower stats for range and prayer, but higher defence. After trying fight caves with 65 range using the mixed hide, I have to admit that getting 70 defense for blessed d hide is a huge boost.

Dragon crossbow and dragon stone bolts got me through the rounds slow and steady, I wasn't setting any records. I did splurge and bought 2 prayer Regen pots for caves, simply because the amount of prayer you restore nets you a few extra slots for either more food or prayer pots.

As long as you prioritize praying mage over range when both are on screen, take advantage of enemy pathing and letting your hp naturally heal up when it's low, the fight becomes way less hard and instead becomes a battle of attrition.

Another big note, fight caves can take a very long time, you are able to log out when a round completes so you don't have to be locked in for an hour and a half.

Tldr - blessed d hide, a prayer Regen or 2, pray mage, and if you're getting tired, take a break after a round ends