I was inspired to produce a low-word-count pangram after seeing Patrick Berry's very Scrabbly 7/15/2006 puzzle. The starting strategy was to get at least two of J, Q, X and Z into the same quadrant. I think I tried seeding every quadrant with just the letters J and Q until I produced what is seen in the NE.
The procedure obviously involved judicious autofilling of successive quadrants; At first I used relatively high threshold values for autofill and eliminated clunkers from my word list with each successive fill, but eventually that left me with very few candidates for completed fill regions. Out of necessity I lowered my autofill threshold and looked for underranked entries which might be tolerated. So, for instance, JAILABLE and UNNAILED were allowed because the surrounding fill was quite satisfactory.
As I moved out of the NE quadrant with J, Q, Z, B, C and G checked off my difficult-letter list, I focused on two main issues: 1. Where to put the letter X, and 2. What to do about G and Z which now spanned two quadrants. (The latter issue was actually more urgent since I probably had plenty of words beginning with EX- … or could eventually invent new ones).
So, as I looked at the G, I decided that the last letter of 14-Down should be something common (R, S, T, L, N or vowel) and specifically considered flexible endings like GHT, GLE, GER, GED and GES. Separately, I decided that 26-Down would probably start with ZIP and 32-Across would have many possibilities ending in UP. This turned out to be a good starting strategy even though the final fill strayed from what I had anticipated. So, the SE quadrant was attempted second — because of the ZIP limitation mentioned above — and a few tentative fills were produced. With each of these candidate fills, I checked off additional letters from my difficult-letter list. At the completion of the SE quadrant, G, F and V were then accounted for, and that mainly left K, H, Y and X to be allotted between the two remaining quadrants.
Beyond the choices for 32-Across ending in UP, I expanded my seeding possibilities for the SW quadrant to specifically include TAKEASIP and HAVEASIP … because they immediately accounted for K and H respectively (while allowing 14-Down to end in an easy letter S. The fill accompanying HAVEASIP looked strong and allowed me to account for the letter Y. So, all that remained was to pack X and K into the NW quadrant. This partially involved luck, but I was also forced to accept one entry beginning with RE- and another ending in –ER. I decided I could live with those two specific words: RESOLE and CUSSER … even if the latter was prominently displayed at 1-Across.