weight and elastic

What materials are you working in? Different materials can take different ammounts of tension, so that may be the main concerne when you are still in the sculpting process.
If you are past that and the doll is allready cast you may have to mod the joints slightly for it to pose right with thicker elastic and, just as you say, drill the challels larger to accomodate it.

I have found that generally, when still in the sculpting stage, a light tension is acctually helpful as it will help in revealing badly designed joints and badly balanced bodies while minimizing the risk of damage. It's not a hard and fast rule, but generally, if a doll pose well with light tension it will pose even better with high tension and if it poses poorly with light tension it will typically be even worse with high tension.

Do you have a project journal for the doll here?

 

The Alien i am working on has digitigrade legs and also had problems standing. I cheated a little by adding a few tiny bumps to support the standing pose.So thats perhaps another (last resort) option to consider.

 

I've been having problems with stringing tension as well, but I'm wondering if my problem isn't the opposite: not -enough- weight. I've been testing different joint styles with 3D printed dolls, and with all but one of them they are either too loose and don't hold together, or too tight and "kicky", or try to do side splits (fixed that issue), or... yeah, you get the idea. It wasn't until watching a video of someone stringing and wiring a doll that it struck me. The doll the woman was holding seemed to have at least a moderate amount of weight to it. The largest doll I have printed is 12.5" tall... and a meager 4 ounces/100 grams in weight.

The one doll I have that does stand on her own has oval bumps on the upper thigh joint, with corresponding divots in the hip socket that help keep that joint stable (thigh and hip are my trickiest spots). The knee is also tightly fitted by design, but the flanges in the back that help keep her upright also limit some of her sitting poses, so it's a bit of a trade-off.

 

Weight will sometimes give higher friction, but considering that even tiny parts such as jointed hands work I think it's safe to say that it is more a matter of joint surface in relation to weight (and tension, joint design, pose etc.) than the weight of the material itself.
It does happen that the balance of a doll changes once it is cast, though.

My personal opinions on "locks" in joints is that they are often just a workaround for a poorly balanced joint, but there are exceptions where a balanced joint would not work on it's own (digitigrade legs is a good example).

 

I completely agree. Start without and only if it cannot be avoided (without completely altering the design or something) add bumps/locks.