They come out easily. Prop case on side in BBQ starter post down. Make sure enough room for post to fall clear of case. Light BBQ close lid and wait for clunk of post falling out.
To install make alignment tool to guide post into correct position for retaining screw. I use a bit of ally rod with a 6mm thread. Heat case as before, cool post in freezer. When ready drop post into position.
I'm here to confirm that the barbecue method of removal is a bit of genius. Nothing to it, and for me, it hardly took any time for the boss to fall out by itself.
One caveat: I have a permanent pedestal grill with a plumbed-in natural gas supply from the city. The type that uses permanent ceramic briquettes. My grill and briquettes are now polluted with oil drippings from the engine case, making it unsuitable for cooking food. I knew this would happen, but that grill is on its absolute last legs, and I don't really use it any more anyways since transitioning away from animal protein.
Here's the boss, now on it's way to Biggles. It emerged from the grill a little blued from oil smoke, but it polished right up.
BTW, I would never do the BBQ method if I intended to re-use the case. If I wanted to re-use the case, I would use an oven. Somewhere, there's a thread that covers how hot you can safely heat an aluminum engine case or head.
Earlier, I wrote that I have removed starter gear bosses from the rear, using heat, a big hammer, and a drift, but it's not easy because you can't get a straight shot at the back of the boss. This pic shows what I mean.
Cutting it out would also be extremely difficult. You'd really need a huge stationary horizontal band saw to get to it.
This little bit of edge on the boss is the only thing you can attack with your big hammer and drift. You're hitting it at an angle, so your simultaneously cocking it in it's recessed case socket hole as you try to drive it out.
So, the way to go is high-heat BBQ or oven.