Last year my pool store where I bought the pool told me to use an 8x15 or 2 4x8 compensators for 15x30 pool. I went with the 4x8's and over the winter one popped the other held fine. The popped one I guess Ice got it since it was sliced. So it did its job
I did buy a second compensator again but trying to decide the best route to go
1) is 1 better than 2 especially since I had that issue
2) On the 2 I just strung rope through them from end to end, a single rope. Into the winter after a storm the compensators slid to one side, both of them. I was debating how to tie these. Should I maybe tie the 2 together in the middle and then 1 line to each end of the pool. I did not secure to the end, just threaded under uprights in case cover got to heavy and sunk them.