Making doughballs (dumplings) with strong brown flour and shredded suet
In the UK self-raising flour doesn't have salt in it, SR flour is just fine plain flour with baking powder in it. In the UK to make a substitution you'd use 150g plain flour plus 2 tsp baking powder mixed in, 100g would be 1 1/3 tsp. In the US most SR flour has salt in it for some reason, so for completeness you would use all-purpose flour plus 2 tsp baking powder plus 1/2 tsp of salt. 

Strong brown flour (whole wheat bread flour) isn't ideal for your doughballs as it has a lot of gluten, and the flour is courser, but it should work okay as long as you:


Add a small amount of water to help bind the dough if they don't stick well
Work the dough as little as possible. SR flour is generally lower in gluten, strong flour is high in gluten, if you work the gluten in the dough it may make your balls stretchy rather. The fat should help to minimize that, but it still helps to stop as soon as the mix is combined
Cook the doughballs longer. Bread flour is courser so may need more time to cook. They may absorb a bit more water than SR flour as well, so be prepared to top up the moisture if you are cooking them in a stew