Apologies for not being clear.
A pot is an integral part of the whole bonsai. To decide whether the pot is too big or too small visually, we need to be able to look at the whole tree and pot at once. Step back and take a photo that shows the outside of the pot and the whole tree. Try to take photos at the same level as the trunk of your tree rather than looking down into the pot.
There's also the horticultural aspect of pot size. Does it have enough volume to sustain the roots of the tree?
The new photo shows a shallow layer of gravel in a deep pot. What purpose do you expect the pot and that gravel will serve? Do you intend that the tree's roots will grow into the gravel in the pot or stay confined to the rock? In other words, is the pot simply to hold the rock planting and the gravel there for aesthetic (visual) or is it aimed to actually sustain the tree?
Making some wild guesses from what I can see, I'd say that pot is way too big and way too deep for the current bonsai.
Perhaps this might give you a better picture of what I mean.
View attachment 589059
I started out with the idea of roots confined to pockets of soil on the rock but it's way too small for that so the roots now grow down the pockets of 'muck' and into the gravel in the tray.
The tray is a suiban - meaning a pot with no holes. It's only 1cm deep and filled with just 10mm gravel, no actual soil. Water fills the pot after watering but usually evaporates completely through the day leaving the roots almost dry but that pool of water is enough to sustain the 3 trees through hot days. Without that extra water they would be dead in days. That's the horticultural aspect of pots size and shape.
Visually, the pot is wide and deep enough to make the planting appear stable but small enough not to dominate the overall composition.
