I'd talk to the Brownell's Tech Staff.
They'll know of anything that's available.
Basically, a bluing operation needs to be either outside under a cover or in a separate room with nothing else in it except the bluing tanks.
The fumes from the chemicals will corrode anything else in the room including pipes and electrical fixtures.
If it's outside, the cover has to be large enough to ABSOLUTELY prevent ANY chance of rain blowing in. One drop of water in the tank and you get a violent steam explosion that blows hot caustic chemicals every where, including in you eyes.
One other option for info is to send a SASE to the NRA American Rifleman Tech Staff and ask them for any info.
NRA members can send ONE question per SASE and the Tech Staff will give the best answer they can come up with.