Wow, Mick...you said you might get into it...I hope to see some examples..

"How the hell do you rough it out with all the projections sticking out?"

Like porcupines have sex...carefully...very carefully.

I also cut off as much as I dared with saws first...made it as round as possible.

This thing was quite unbalanced....had more weight in one inside area than the other, so it was slow and cautious, using tools with the least 'catch' quotient - that is, small sharp points on heavy tools, until I got it down a ways. Inside, it was even harder. as I had to brace my tools very carefully. This was as hard as anything I've done, and it seemed to take forever.
Usually, on smaller pieces with limbs & roots and such sticking out, the trick is to turn them faster, so there's shorter time for a tool to 'catch' between spaces....but this one was too big to allow that much torque. I just let it go whap, whap, whap, taking very light cuts until it was sorta under control.