Bonnie Hunter has size charts for setting blocks on point underneath her free scrap quilt tutorials on her www.quiltville.com site. Perhaps something there might help.
Welcome to the Quilting Board!
I also sew the seam from the back so I can see where the point is. Also you can "float" you point by squaring the block 1/2" larger than needed so when peicing the points do not touch the edge. This is the method I used for Elenor Burn's winning hand quilt. Using this method may meen that you have to adjust the size of other blocks. The "floating " points have a nice look.
What does sewing from the back mean? You don't You don't put right sides together to sew? Sorry if I sound dumb,I feel dumb for sure!
the biggest problem most people don't watch for is making sure the seam has an even amt of fabric on each side of the seam on the points. this will make your points go wonky.
Here is my tutorial on how to keep your points and troubleshooting ideas to fix your points.
My tips for making HST's and not losing the points
I agree with Joyce888 and others. If it calls for a block size of 3 and 7/8 to make a 3 and 1/2 square I cut the square at 4 in. it gives me just enough to square it up. I, too, am a pencil down the center sewer of half square triangles. Squaring them up is key to a perfect quilt. I also use the idea of sewing on the back to see where the seams are.
Accuracy is the key to getting the points right. If you take the time to cut accurately and take the time to fix anything that isn't straight and accurate then you will get good points. this is not a place to say oh well it's good enough. Biggest thing is to make sure you have a 1/4" seam allowance left between where your seams meet and the edge of your fabric when you join hsts.
When I see a quilt block that doesn't have enough seam allowance left on the edges you know the points will be lost when it is sewn to another quilt block. This usually is a quick fix if you just tighten your seams.
there is a DVD called "Triangulations" by Brenda Henning, that makes HST and QST very easy, and no trimming needed.
you print up a page for the size you want... use the 2 large pieces of fabrics the size of the paper ....paper on top... you stitch and then cut. press, and perfect HST and QST
Life is what happens while we are busy making other plans!