Could someone explain the difference between the two and what are the sizes of the rulers. I can not find the exact measurements of either. My DH wants to make me one as I'm on a budget as everyone else. Thanks for any help.

go to http://www.quiltingboard.com/t-57130-1.htm

NOTE: measurement should be 3/4" from all corners, not 1" on top right hand as shown.

Never made a pinwheel. But I have made a twister. I made my own template out of cardboard. (No money lost.) Go to the page mommamac suggested it will help.
This may also help:
http://www.quiltingboard.com/t-87084-2.htm
Pictures on bottom of 2nd page.

I have seen some say do 3/4 at every corner and others say that the 1 inch on the top right Which is correct ????

Do I come in an inch from the template using a 4 1/2" square or 1" from the corner of the block. (1/4" seam). I did copy a diagram from www.quilterscache.com/images50/pinwheels5temp.gif which might explain my confusion. Thanks so very much for the help.

the lil twister I purchased is 3/4" from every corner of a 3 1/2" square - I wonder if the people that use a 1" on the right hand corner changed it up so they wouldn't be copying a marketed template??

You need to make & mark a template with an X as shown in picture of above post I gave you. The blocks you are using should be 5" to begin with. If you scroll down in the post from 'bstock' above, you will see picture of how to start.

I think your confusion lies in the fact that the twister is a grid of 5" blocks sewn together before cutting. It sounds like the pinwheels are individual blocks.

the templates sizes are 3½" and 8". I have made both the pinwheel and the twister and prefer the twister for the ease of cutting and sewing. To make the traditional pinwheel, it is time consuming and requires more sewing. The twister is very forgiving if you can't get an accurate ¼" seam.