I'm looking for a light strawberry buttercream recipe that is crusting and not too sweet. Thanks!

Crusting requires a larger proportion of dry (powdered sugar) to fat (Crisco) in a frosting recipe.

Here's a light & not too sweet frosting recipe that has light crusting:

http://www.cakecentral.com/cake_recipe-2019-Whipped-Cream-Buttercream-Frosting.html

indydebi's b/c crusts very well:

http://www.cakecentral.com/cake_recipe-6992-Indydebis-Crisco-Based-Buttercream-Icing.html

Sustitute strawberry extract (I use McCormack's) for the flavoring indicated in the recipe/s.

HTH