PPS Re switching the triangles - I know lots of ppl do it just for fun and it's fine but I only do it to avoid repeats of the same block or if I feel I have to manipulate the design a certain way, eg to emphasise a particular colourway. If you put a colour in the centre of a block, in general it has more impact than it will round the edges.
Anyway, of course you can switch every block around if you like but you have to then be really careful of the bias. I don't starch my fabric before cutting and layering - the first starch it gets is at the pressing of seams when sewing the blocks stage. This is because a) the fabric should be unwashed so it still has it's sizing from the manufacturing process tus starch isn't necessary and b) I feel the wetness of the starch may distort the pattern repeat, especially in a lower grade fabric with a smaller thread count. But that's my personal feeling. I know lots of ppl who starch liberally. Just be gentle with that bias!