Easiest consumer grade silicone(s) to find that are 99.95% inert during/after curing are aquarium glue/sealants.
Inert *after* cure I'd agree with, but unless your silicone is very different to the stuff we have here - not during.
One of my best mates was a glazier for 25 years, and made more than his share of aquariums - and said that the only decent stuff that actually stuck to the glass properly, long-term, was the acid cure. Until recently, all the neutral cure stuff also goes "foggy" and never really stays clear.
Whatever stuff you get, get the materials spec for it. Unless it specifically states it's neutral cure, don't use it on electronics stuff, or on metal - especially in enclosed spaces with exposed metal of just about any type!
