Just now reviewing this thread and enjoyed seeing your process, thanks for sharing it and your practices.
I'll share a bit of my last pool practice in this regard, and although brief (approx. 40-45 min.) produced a good sense of efficiency.
I tasked myself to take no more than +1 of my initial repeat during tune-up, and improve on it especially if I felt it a bit high for this exercise.
Tuesday August 11 @ Y indoor 25yd pool
I began with a 200FR w/u followed by 4x100FR t/u and then rounds of 4x50s FR @ each tempo setting... 50BK between rounds.
TT 1.05... :40
TT 1.07... :40
TT 1.09... :40 *here I dropped one stroke!
TT 1.08... :40 * here I kept glimpsing :39 and so decided to tick up tempo by .01 on fourth repeat
TT 1.07... :39! *and stroke count remained!
Next I returned to starting tempo
TT 1.05... :39 * and stroke count remained!
With time running I sensed I'd played this card out so I up tempo by .04 for one repeat
TT 1.01... :38 *and stoke count remained within +1!
Back to starting tempo for next three repeats to see if any 'magic' occurred and...
TT 1.05... :39 *and no real magic but held on to my stroke count and time from last round @ this tempo for an easier repeat average, done!
Warmed down with 1x100 BK/FR
I never took more than 14spl for the entire practice!(w/u and t/u were @ 12-13spl) A big confidence builder and good marker going forward.
I like practicing at the lower end of my range, not to advocate swimming at low stroke counts, but find that I benefit from it going into longer more demanding practices and swims, allowing for more efficient, speedier and 'easier' swimming.