Exercise Order Matters!!!
It has been well documented that large, compound movements, involving multiple muscles over a number of joints stimulate the release of growth hormones acutely (ie dead lifts). Conversely, isolated movements, involving small muscles across a single joint (such as the bicep curl) have very little effect on growth hormone release. The practical relevance of this observation is that large compound movements performed prior to isolated movements will result in far greater growth and development of the isolated muscle; eg bicep.
In rock climbing, the number one predictor of climbing performance is time until fatigue. That is, the time taken for the forearm muscles to become fully fatigued and unable to grasp the holds. Technique, body fat percentage, age, nutritional status, anthropometric measurements etc all play factors in this equation, however, all factors the same, time until fatigue is the number one determinant.
Therefore, increasing the time until fatigue will, assuming all factors are the same, have greatest effect on your climbing ability…