Along the edge of the baseboard joint, there is a meniscus curve in the canal. I've been putting off dealing with it but eventually had to do something.
The Woodland Scenics Deep Pour resin is pretty solid, so with no better ideas, I attacked it with a sharp knife, sliding the blade along, trying to cut slivers of "water" away.
This sort of worked but eventually I resorted to scraping the blade sideways in the same way I remove mould lines on a plastic kit. This worked, but the slightly rough surface (above the blade in the photo) didn't look great. Not as bad as I feared though.
A new blade and back to the slicing - the results aren't bad. Not perfect, but then I didn't expect that. The resin is a little rubbery, so not amenable to polishing with abrasive. The result doesn't stand out too much though. No worse than a baseboard joint anyway, and I still plan a pipe bridge to hide it further.