What is the smallest 'sustainable' bonsai size?

[blackadam]

so getting low bends is difficult.

That is the interesting part, they were wired as seedlings and then let thicken? Description of starting process and then watching progress pictures would be great

Only few make it to this level.

One in ten? 20?

 

[Shibui]

Description of starting process and then watching progress pictures would be great

Most of those shown were selected because the seedlings already had low bends - probably from the seedlings growing through mulch or stones, etc. I've seen this done artificially by germinating seedlings under a layer of stones, shade cloth or plastic film but have not tried any of those so can't give you a percent good v rejects.
A couple were wired very young. That way you get to make all the mistakes. Reject rate is still more than 9 in 10.
The JM grew over the wire before I realised it had thickened. Wire is still in there somewhere. That's a technique that's been used on pines because the rough bark hides the wire marks. Not usually used on smooth bark deciduous but I kept it to see how long it would take to hide the scars.
The Cascade cotoneaster was wired as a new rooted cutting.

 

[Shibui]

One in ten? 20?

Probably way less than 1 in 10.