I will play the devils advocate here, i love using materials that I have found or have from my property. I do not sell any of these but they make great momentos. The answere to your first question is yes they can dye and stabilize at the same time. Depending on the wood you may not need to stabilize but can use a wood dye only. Prior to sending it out it does need to be dry, in the wood pile may not be enough if it was in log form, take your spits and paint the ends with any paint and let them dry for a few months. That should be the end of the cracking, cut your blocks and let them set for a while longer. If you are going to rush things, cut some blocks now and set them in a warm place and see if they crack before you strart on your handle. You can also try to dry the blocks in the oven or microwave, you can google search this, many workworkers will do this but it will increase the cracking. you need about 5" for handles, I would cut blocks at least 7" to make up for any checking on the end.