Thank you

I looked there, but they don't have tapewound strings. I feel silly for putting on awkward strings in the first place
They do have Rotosound black nylon tapewound (Tru Bass 88) singles, if you already know and like them, or feel like experimenting:
[Invalid or Expired Link Removed] and [Invalid or Expired Link Removed] (might have to file the nut wider/replace it with one worth sacrificing in the name of nylon).
schneidermusik.de has the Galli tapes available as singles, same gauges (
here -
here), but IIRC has a flat shipping rate so you may want to browse for something else and make a more substantial order to make it worth buying from them.
(Have bought from both online stores, would recommend both, otherwise not affiliated.)
No other options that I'm aware of (yet).
EDIT:
the Rotos and the Gallis might sound a little woodier and darker than the D'Ads according to user descriptions and manufacturer blurbs.
If you do try either one, and a mixandmatched single tape proves mismatched soundwise,
and you find out you care more about sound than feel, you might wanna try a ground- or pressurewound single, maybe with a small mute (foam, cloth or paper) under the E only, to tame its upper end.
You could also consider trying a
Invalid Link Removed. Check out Ric5's recording of his Rickenbacker 4004 cii with the tapes it came with
Invalid Link Removed. User Root 5 believed they were Fenders (see post 10 of that thread): if that's correct, judging from the soundclips I would put them firmly in "dead round" camp soundwise: probably too bright for some. (There might be more clips of Fender tapes here with no doubts as to their attribution: use the search, Luke!) They definitely don't break the bank at 15.36 quid.