Brad:
Here is a picture of some of mine:



As mentioned you should use a softwood head and a hardwood handle.

If the head splits and falls off, just replace the head by sliding a new one onto your old handle.

I have the first handle I ever made, and I think this handle has the third head on it now.

Rounding off the corners helps prevent damage to timbers, or as mentioned use a "pad" block of wood between commander head and timber when striking.

Also, joints shouldn't "need" to be pounded together, test fit and pare as needed so that the slide together without pounding.
But of course there are times when they might need a little push...

I have used 6x8x14" stock for heads, as well as 6x6x12" stock for smaller ones.
Different sizes are for different uses.
I wouldn't take the largest one up a ladder, use a smaller one...

Jim Rogers