Whats your go to method of having a head and body fit together?

Is the SD Soony the Feeple60 one, and are they on FL bodies or are you hybriding them into something else?

Many Minifee heads in general are wobbly on the neck connectors, but the Juri 14 head is really bad and sometimes doesn't fit on the connector at all. The wobble doesn't bother me since it doesn't affect posing and isn't at risk of falling off, but if it did, I would probably just stick some white tac in between the connector and the head.

If you're doing hybrids with them, you might try a different replacement neck connector. I've never had a F60 neck connector for my F60 Soony, but I use the one from Shapeways and she doesn't wobble.

If you have the Delf Soony, it needs an old-fashioned "neck donut" to sit on the neck hole. I'm honestly not sure where you could buy one of these new anymore but I've found them pretty easily secondhand.

If the issue is that the neck on the chosen hybrid body is smaller than the neck adapter (since none of the Soony heads have a proper neck joint) my go-to solution is to stick a silicone washer in there.

 

I use eye putty for my loose FL heads, to hold the head to the connector. Luts still sells neck donuts if it's the Delf Soony; they're listed under Delf option parts. Silicone washers are my go-to for other brands as well, except I buy craft sheets of clear silicone and cut my own (circle stencils and a craft knife) so I can get whichever thickness and size I need easily.

 

I don't have any FL or Luts specifically but I use hot glue on my loose heads. Silicone washers tend to shift and move out of the neck joint (especially if there is a big hole for the hook) but hot glue allows me to make the head sit as I wish.

 

Hot glue is safe on resin (as long as you use a low-temp gun, which the cheap craft ones usually are), it's also used for sueding for better posing quite often. If you mess up or want to adjust, you can just peel if off and try again

 

I have two hybrids (hoping for more in the future as I am waiting for a head) I didn't had much issues matching the bodies, but I did used hot glue to make the head more steadying.
There's lots of tutorials on YouTube about sueding using hot glue. It's a very easy and quick method.
Neck doughtnuts is another alternative.