Hey Art.
I used a spot in the basement of the Liquor shop, I had 4 sheets of plastic that rolled up and down like window blinds to keep the dust off the bottles of booze
The hatch I had to fight tooth and nail to get, they did not even want to give me that, the wall there is about 60cm or so thick, and is structural. I had long heated debates with the architect about it, he did NOT want to do it, but was finally swayed by my argument about if I ever have a fire (knock on wood I don't!!) I'd at least have some area to escape to, if I could not get out the hatch.
Yeah it sucks, I would sure be nice to have the Annex space too, but that was not in the cards.
As it is, my "Man Cave" is bigger than almost anyone else I know in Tokyo
BTW, I'm not done in the renovation, but I am out of plywood. I might go on Monday to get some more, maybe, depends on the weather, as it is actually snowing right now, and the say we will get 3 to 5 cm of snow today.............. I know that is not much, but if it sticks, Tokyo WILL grind to a halt!
Cheers!