the 8 1/2 is the largest saw we are using every day......i have a 10in millwakee that sits in the box, i could sell it to ya very reasonably

I do like the electric chainsaw quite a bit and I feel it's worth spending some dollars to get something decent. Lines can be cut with a circular saw, then the chainsaw can finish the cut back of the line a bit, the center of the cut can then be ground off somewhat using the chainsaw and we follow with a small power planer and finish with a block plane when neccessary.

I think you are right to respect the bigger saws, especially a big saw with a dull blade. If you could find someone who has a bigger saw and visit them to try a few cuts that would help, otherwise i would step up slowly in size(although i write this having never tried the 16" makita).
You would also be wise to respect the electric chainsaw, in my opinion a far more deadly machine than any circular saw i've used. I would suggest a hard hat be on your head every time you cut with a chainsaw of any kind......
When a saw (circular or chainsaw) binds, it is best to back up and slice some wood away from the waste side of your cut, this should free the blade, allowing you to straighten out and cool down.
ok, take care and work safe.