Need new skimmer

[RH60]

Looking to change from an old LOmart skimmer in a 18 ft AG pool. Steel coated walls.

Is the Hayward SP1091LX a good choice?.

Also what gauge metal. Plan is to get a piece of stainless sheetmetal and do the cut out for the hayward. Then patch on exsisting pool. What gauge should I ask for?

Thanks