Help me find the right size uprights for my pool

I have a pool from Home and Roam from Baltimore. Here are a few details:

  1. Pool size: 27 ft. round pool, 52" deep" wide, 15,000 gallons

  2. The uprights measure 5"W x 52"H

3, Top and Bottom Brackets are 51/2" wide.

  1. Pool is at least 22 years old.