poolpup,

If I were constructing a 40k pool for you it would have a 1 1/2 hp (no spa) or a 2 1/2hp (spa) pump size.
I'd use 2" lines with 2 dedicated skimmers and a dedicated main drain, these pipes would come back to the equipment pad and be individually valved.
The filter would be either a 60sg/ft DE, 36" sand, or 500sq/ft or larger multi cartridge filter. The cleaner would be a booster pump assisted Polaris 280 or Pentair Legend.

See Ya,
Kelly