If it helps, I've just managed to build 7C's with Arai8000 sealed hubs (which are dimensionally the same as your hubs I believe) with 186mm spokes 3X and short nipples and my LBS got full tension on them. 184's seem tricky to find it seems for some reason.
The wheels are on my BotM entry Team Mongoose if you want to have a look (shameless plug for votes....!)