Having flown 737-800s with and without winglets, my personal experience was that for a heavyweight near max landing mass aircraft, my continuous descent approaches needed speedbrake when using non-winglet energy management maths for idle power path control in the winglet version.
Better results were obtained, without destroying valuable energy obtained from the fuel tanks, by factoring my IAS-reduction-to-min-clean distance by increasing it by 50%.
I have never noticed the reported near-ceiling struggle, but we're using 26k engines, which means the -800 does what it says on the tin!
Hope this is of use, though not the right a/c type?
