You can trim off the little tabs at the same time you trim the square just by angle cutting the two corners before opening the square. Be sure and read the instruction page because it has all the sizes from 1 in to 6 in. It is just a matter of adding 2 in for each size larger HST you want. 6 in squares for 2 1/2 - 8 in square for 3 1/2.
I have tried triangulations, it is not as easy as El Burns and no paper. They dont always come out the right size because of imperfect sewing and fabic stretch. I prefer to oversize and trim.