@dalehileman,
1A: I stood clinging to one of the metal poles (,) which helped me balance
An attempt to clarify: Without the comma, the tense "helped" suggests at least one past experience in which at least one or more of the two or more poles had proven to serve his need and that his last clinging refers only to a stable pole, "helped" referring to "one of the metal poles"
Thus he could have written, "which
had helped me balance"; and if only two poles, "one of the
two"
Thus I might have stood clinging to one of the two metal poles which had helped me balance. However this is complicated by the inference that both were stable
We must also address the possibility that some of the poles weren't metallic