GG check out Flame Defender extinguishers. They are a must. FLAME DEFENDER FIRE EXTINGUISHER - 4.4 lbs / 2 KG Covers 4' (1.24 meters diameter) [740702] - Miscellaneous - Accessories - Discount Specialty Farm, Greenhouse & Garden Supply Store - Horticulture Source

Also, put the alarm in both rooms. They are cheap and you may get a few more minutes notice if you happen to hear it. Ideally it would be hard wired into your house-wide system so if triggered it would set off the whole house. I'm rewiring mine at the moment to achieve this result. Can't be too careful.

Oh and did you install arc and ground fault interrupters at the mains? Also a good idea.

Nice work here. Would love to hear about your sulfur burner.