OnTheGo

I am so sorry about your grandson. A quilt made from his shirts will be a wonderful memorial.
There have been some very good suggestions already posted, especially about using stablilizer. I used the iron-on batting which is bought by the yard and looks like felt, however I was not really happy with it. It didn't stick well on some blocks.
I used 16 blocks that were 16" finished with 6" finished sashing strips and 6" sq. cornerstones to make a 94 inch square king quilt. At least I believe those are the correct sizes. The quilt is with my daughter in Kazakhstan, so I'm going by memory on measurements. I put together 4 sections of 4 blocks each including sashing & cornerstones. I top stitched with the machine through all layers 1/4 in. from the seams of all the sashing strips so that showed on the back. I set them together like the tutorial in the link I am sending. The only difference is I sewed my 4 sections together with the seams to be hand finished on the back rather than the front and it was a cross (+) once on the back side rather than for each block. I made up my method as I went along, but if I did another one, I'd use the QAYG per block method like the tutorial.
http://www.quiltingboard.com/t-52698-1.htm