Any ideas on how to set/output something if the previous variant in a for loop has a parameter? Realizing Twig can't escape a for loop, how would one go about setting a variable for the current item and not the following?

Scenario;
Color swatches are radio buttons, if default purchasable stock &lt;= 0 and default purchasable unlimitedStock == false, the next radio button should be checked, and if this has stock &lt;= 0 and so on, you get the idea, the next would be checked.

I can't seem to find a way to only check the next, and not all the following radio buttons if previous purchasable in the loop is out of stock.

A lot of checking of the checkers being checked here. Hah.
Check out the MN Twig Perversion plugin. It adds a break Twig tag, which allows you to escape from a loop once you have the data you need.