Hi Tony, so for blending your current shaping is not good for it because the round part has such a hard change in direction in a small area here:



A blend surface is going to make itself be smooth to that and it's going to need space for that so you'll be limited to something like this:


To make it larger you would need to adjust the shaping of the round part, it needs to be something more like this where it's not such a severe change in direction between the pieces:


- Michael