You could start with 2, instead of 3, on point. It would be 2,3,2,3,2,3,2. Thereby using all 17 blocks.
Then perhaps the largest triangles would go in in the 4 corners, and the other triangles on the sides (4) and top and bottom (2). Or, if 14 of the triangles are all the same size, you could use 2 in each corner instead of one larger one.
I don't know the sizes of all the parts, so just taking a guess.