There are two types of antiscald technology available for showers: pressure balance and thermstatic (and some combine the two). Either should work. the consideration for any valve, doesn't matter the type, is to ensure you get one big enough to supply the desired load without restricting the flow, and not being able to provide the desired impact. This normally isn't a problem unless you have a lot of heads you need to supply. A 1/2" typical valve can flow about 5-6 gpm. If your shower heads need more, then you need a 3/4" valve, and 3/4" lines coming into it, so that may be the bigger problem.
When making changes in your plumbing, it is rare when at least some soldering is not required. Maybe it's time to call in a plumber...
Soldering isn't all that hard if you have any handy gene at all. Buy some fittings, a hunk of pipe and the required cutting, and soldering tools and practice a little. It's a handy skill to have, and doesn't take all that long to learn. While not quite the same thing, it takes about 10 hours to train a new person and certify them for electronic soldering to mil-spec abilities. Soldering pipe is a lot less exacting.