Maintenance Elastic too loose or knot needs to be tied tighter/shorter?

If you can, try to measure the diameter of the elastic he currently has. That will give you an idea of what to look for, even if it isn't from a BJD store!

As for floppiness, is it an issue of standing or posing? Can you see any gaps between his joints or parts? If you pose his arms or legs, do they remain in that pose? All of these things can tell you a little bit about his condition. Generally speaking, the elastic is too worn out if you can see gaps but it doesn't hurt to try yanking up his elastic to see if that doesn't alleviate it temporarily while you do it.

 

I think that the 4mm elastic is better for them. I'll sometimes use the 3mm elastic for the arms, but the 4mm for the one that runs though the body. The 4mm elastic is sturdier and more likely to hold up under the larger dolls weight.

The 1/3 elastic on Alice's collection says 4mm for body and 3.5mm for arms.

I personally found the 3mm didn't hold up on my larger dolls when I ran it through the body. I bought my 4mm on eBay, in the doll repair section.