Need some guidance on wood floor fitting - balustrades

[stanwan]

Hi all,

Thanks to all the helpful folk on this forum I've succeeded in fitting engineered wood to most of the house. The conundrum I have is the hallway and in particular the balustrades. The original construction is for carpet - the base rail sits on a nosing that is level with the subfloor and the original carpet was butted up to the base rail.

I am wondering the best way to approach this? I was also planning to replace spindles and handrail at some point.....

Do I simply attempt to undercut the base rail and slot the flooring below (structural compromise?), butt up (no expansion gap) or shim up the base rail height with ply so the expansion gap can be hidden.

When it comes to the newels, am I safe to channel out 10mm for expansion, or should I just trim with scotia?