When I click on the eraser and switch to the unerase tool if I change the size it automatically switches over to the erase too. When I think click back on the unerase tool it sets the size to the default. So there is no way to change the size of the unerase tool.

I made a short video which explains it. It doesn't appear to have attached to this post. I will send it in an email if I can't attach it to a comment to this post. The first time I clicked the attachment icon it actually wiped the content of my post. I was careful to click the attachment icon, not the cancel button next to it. So I don't want to take the chance of having that happen again.