@phangtonpower @Nashrakh:
As I related a number of times here, I wasn't in love with a single short-scale flatwound Rotosound .09 E string (actually two of them) I tried some time ago: beside being a little too thumpy-sounding for my needs, it managed to combine very low tension with inflexibility. The result was a marked bump in pitch on the attack which I found difficult to work with.
Based on that experience, I'll go out on a limb and suggest that, somewhat counterintuitively, the .104 and .105 from the DTB 760FL and -FS respectively may in fact work better, or less poorly if you will, when downtuned a 4th than the .109 and .11 from the -FM and -M (1954) sets because of the latter gauges' higher stiffness making them more difficult to intonate and play without hard-to-control pitch envelopes when they're tuned below a certain threshold. As for where said threshold is, many report on the Jamerson set being a fantastic (long-scale) D standard and short-scale (E standard) option.
If I were in @Desuh's shoes I'd consider putting together a hybrid set made as follows: basically a 5-string set of 1954 gauges but without the .11 in question, IOW .052 .073 .095 .128T, with the caveat that, having not tried it myself, I can't say for certain that the now-detuned, originally G-D-A strings will not exhibit the same behaviour that I've tentatively attributed to the .11 based on reports.
Well, either the above, or just trying the (BEAD available gauges of) Low Tension Flexible flats La Bella makes...