I have an old house which probably dates back to 1920s or so. Most walls are plaster and the outside walls are brick. Tenants in the 80s or 90s did not take good care of it. It was rehabbed, quickly and a bit shoddily (which I did not really discover until after I bought it). So there are tons of examples of cutting corners (literally; when we removed some drywall to do some work we discovered one corner did not actually have a stud supporting it).
We had a handyman lay the floor but not the trim. He installed it against the existing baseboard and I'm installing shoe molding to hide the gaps.
The dining room has around 10 feet of base molding which bows considerably, as does the wall behind it.
I've heard people mention that sometimes older homes used green wood which bowed when it dried. Here's the thing, though: when I push against the bottom of the wall, it gives noticeably. I'm wondering if it's possible that this wall is not really attached to anything — at least, not in the bottom middle — and if it would be possible to attach the base of the wall to something sturdy behind it (probably the brick as I'm not at all certain that there are studs there that I can use) so that it no longer gives or bows.
If this is a bad idea for some reason, what are my options for attaching shoe molding? Do I just force it against the curved baseboard? Do I cut it into shorter pieces to compensate, and angle the lengths accordingly?