You'll need to go to the manufacturers' sites, and check. You know you need 2 covers; each should be rated at 350 GPM flow. The recent anti-entrapment regulations has resulted in manufacturers' publishing rated flow data. You can look through your options here:
http://www.hayward-pool.com/webapp/w..._Spa_Equipment
and here:
https://www.pentairpartners.com/prod...WhiteGoods.pdf

You'll want to record EXACT Hayward and Pentair product numbers. Most retail stores, including online stores, are NOT familiar with, or knowledgeable about, commercial pool gear.