Just as a general note as I'm working on updating the OP - Looking into desynthable items in the gap between ~170 and ~240, I'm basically finding that there are only the two obvious options for non-CUL desynth. For ~170 to ~200, PvP i180 gear. For ~190 to ~220, PvP i205 gear. For ~220 to ~240, Poetics i230 gear. Then you can do the i255 stuff from SB, and use vendor/MB bought gear from there until you hit the SB endgame and have only dungeon drops to finish your way to the cap. There really aren't many/any other options, unless you are spamming HW dungeons for gear, which is extremely unreliable.

I still need more datapoints to get the new formula up, but it seems they extended the bonus desynth chance again, resulting in r230 gear having a success change of 80% at dSkill 230. That really helps with the gap. Also, you can desynth items that have an 80-100% chance and still get 0.7-1.0 dSkill with that gear, if you're in the right dSkill range. So, at least you get a level up almost every time you desynth, which helps close the gap.

More later.