I m I private snow contractor. The power broom is expensive, but it works.
I have a few drives that are gravel and I have tried many methods over the years. It sounds good to just let it freeze down before plowing, to plow with a board on the bottom of the blade, plow with the feet at the highest they go. I have tried them all.
I bought one off of craigslist a few years ago, and they work. Now if you have a large pile you may not get that all the way back onto the drive. Before buying it I did not even offer coming back to take care of what ended up in yards. Now I have just raised my price a little and include it in the spring.
I have used it many times, and it really does not do much to the grass. The only problems that I have encountered it were I will pile snow. There is just to much to get it back. I will usually just pile it as far as I can, then shovel a few times then start over.
If you have done it as much as you say, and are careful about not getting rock in the yard. It would be a breeze to do that much driveway.
Mine is an echo and not stihl, and I know others are making them. Look into the combi systems also. I am not sure the broom sort of attachment show on the tractor works that well. Mine also has that, and it did not work as good as the rubber flappers.
I would bet a rental would have something. Or a landscaper might that could come out and show you how well it works for a price. Especially if one does snow removal also.