I would get a big piece of paper out and draw several of the first square sizes (minus seam allowances). I would then take my Twister ruler and lay it on the paper as if I was going to cut out the twister shape but instead trace around it with a different coloured pencil. Do this for about 4 to 6 blocks and see if there is enough room between the twister blocks to rotary cut out the shapes from your reduced material sizes. It will take the guess work out of it and will let you know if you need to buy more material. There is some fabric space left usually between the Twister cuts so you might have enough?