Finishing / Filling base of stair spindles - choices choices

[not_an_exit]

Hi
I've just had some new stairs put in. The spindles need to be painted, but I have a load of gaps around the base of every spindle (see photos). I am thinking about how best to finish this area. I could fill the little gaps with polyfilla, wood filler, or decorators caulk. Or leave as is, paint it and hope for the best. Or something else that I haven't thought about. Any ideas about the best solution?
Thanks for any help!

[RustyMX5]

I found that the issue with filling small gaps with filler is that you need a really small spatula of some kind to work it in. Then you'll need to do some fairing and repainting. If it really bothers you then decorators caulk and some smoothing tools should give a neat finish. Don't use your fingers to smooth things as it usually ends up looking uneven.

[Lotobear]

Several coats of undercoat will flood those gaps and act as its own filler.

[not_an_exit]

Thanks for those replies both. Seems like I should try the undercoat solution first (easier), and if that doesn't work then resort to some sort of filler. Thanks for the help!