Prepare New Foam Blocks
I used 30mm solid foam as the blocks to spread the bow out to the new specifications. I took measurements as I worked to make sure the hull was spreading in the right places. The top of the hull will need to be drawn back so that the deck does not become overly wide. I also marked the inside of the hull where each block would fit so it was easier to put blocks back in about the same place and achieve approximately the same spread from initial measurements.
Below are two pictures of the same bow. The left picture is the original hull shape and the right picture after foam blocks are inserted. You may not see it but there is up to 20mm more width in several places.