I am also currently more into simple traditional patterns (not pictured) than doing the whole MODERN quilt thing, so I was looking through one of these 'so you want to make a lot of quilts really quickly' books from the 90s, and found a quilt I really liked, twin sized, which is my thing, and is just 7.5" Double Wrench blocks set on point.
And anyway, what drives me and people like me crazy is that, of course, the names mean nothing! They were used and reused and assigned to blocks that don't even relate to each other. Much like one imagines the state of animal taxonomy was prior to Linneaus.
But here is my quick block analysis. The corner units are half square triangle squares, and the center square is half the size. For a Churn Dash, all the subunits are square, a nine patch layout where the center block is the same size as the outside hst units.
And here is some size information:
N.B. - the hst subunit size is the size of the subunit once the two triangles are sewn together, the finished size of the subunit in the quilt will be (as with the squares) 0.5" smaller.
for a 5" finished block (like the one above), use (4) 2.5" hst subunits and (9) 1.5" squares
for a 7.5" finished block, use 3.5" hst and 2" squares
for a 10" finished block, use 4.5" hst and 2.5" squares
Other sizes are possible, but would require more thought/math.