Is 20'-25' too close for sprinkler rotors? How far do pros usually place them apart? I always see pictures of irrigation systems, and they look like heads are 40'-50' apart with a great head-head throw. I don't have lots of pressure or gpm.

What kind of rotor would be the best? Its in a high traffic area, and I plan on $12 max each head with the shipping.

I planned on either using the Rainbird 5004 head or PGP Ultra (upgraded/better PGP-ADJ). What would you suggest?