Yes, I built it for multipurpose use, the 50' length was the minimum I thought it needed to be for laps. It gets more use as a recreational pool in the wide shallow end and tanning ledge. The tanning ledge is my wife's and the dog's favorite area! Though yesterday the water was finally warm enough the wife swam some laps!
I think the 50' length works great, have not thought once that it needed to be longer. Not sure what you mean about being a strong swimmer, I'm not pounding out the miles in laps every day, work gets in the way. I'm also not training for any type of event, triathlon, or swim meet. I have done a triathlon in my younger days and love to swim.
We have one return in the shallow end and then two in each long side, seems to work well, stuff can collect back on the tanning ledge, a few sweeps of the brush help with that.
I'll be happy to answer any other questions the best I can.