My experience in a 50m-pool was like this:
. SR 34 from 1.6 to 1.8
. SR 32 from 1.9 to 2.0
about the same when going down the "beep-pyramid".
I liked it, had no problem with balance, gliding,...
My problem seems to be that I can't "use" the knowhow of gliding when trying to swim faster. Seems I end up in a kind of struggle when I try to use the high elbow more effectively, try to grab the water,... I'll try to use the TT moreoften and see if I can get a better SR with less beeps.
Thank you Terry to "allow" me to swim much slower than I usually do :-) (usually I feel o.k. with ~ 1.20).