For cost, one turnover per day would require about 7 hours @ 1.8 kw with your current pump and plumbing but only 6 hours @1.9kw with a pad change. So a monthly difference of 36 kwh or 144 kwh per year savings. Multiply that by your utility rate and you can get the savings per year. Even at the higher energy rates, it is probably not worth the trouble.

For pump sizing, the smallest SuperPump is a 1 HP uprated pump two sizes down from what you have and would provide about 60 GPM on your plumbing or about 2.7 turns per day. Fixing the pad plumbing would bump that up to 68 GPM or over 3 turns per day which is plenty.

Another option would be to just replace the motor with a two speed motor. If you ran on low most of the time (2 hours high, 10 hours on low), you could save about 550 kwh per year. Still not a lot but could pay for the motor in a few of years.

If you normally run 2 turns per day just double the energy savings.