An interesting procedure, I do something similar myself - but only during the rigors of winter use & abuse as the rock salt & calcium chloride they use on the roads around here simply eradicate any traces of lubrication with as little as one ride, chains protected with anything less generally only last a week before they become corroded, a month before they're unusable (binding links).
Having said that, the reason I don't use it in all seasons is even in the warmer temperatures the viscosity of most automotive bearing grease is such that it can cause ...well ...not bound links exactly, but "lag time" if you will, slightly gummy the links don't quite move as freely as with thinner lubricants.
This may seem a minor point, even irrelevant - and it pretty much is with the typical 41/410/415 kit drive chains, but with the 3/32" bike chain we almost all have as well, it can exhibit some interesting behaviors when packed with thicker greases, particularly during deceleration or backpedaling w/derailleurs as the chain can arc over, instead of laying on/in the cog's teeth. If there's any lateral force, that chain can now happily hop off. It can also contribute to chain slap/whip* - where it smacks the stays & generally makes a nuisance of itself.
Admittedly, I've not tried a 30% graphite powder mix (and I defo will, thanks!), but I have tried diluting bearing grease with other additives, motor oil, machine oil, & "bicycle chain oil" (likely just expensive machine oil lol) & even solvents like kerosene, denatured alcohol & acetone to try to dial in that perfect consistency... so far, it's jus' been a messy waste of time, there really wasn't much difference unless thinned to the point of pointlessness, as I just made myself chain oil, with all the same problems that cause me to try grease in the first place >.<
Now to be clear, this is a very minor problem & one unlikely to be experienced with a chain as heavy as the kit's or one that doesn't require or have some amount of slack (idlers, tensioners & derailleurs oh my), but I just wanted to say thanks for the tip - and caution that you might experience some technical difficulty with lighter chains jus' in case
chain slap/whip* = there's a term for this & that may be it, not the tool "chain whip" obv (used for removing cassettes) but when the chain smacks the stays/frame not due to alignment, but slack, usually during deceleration... bejabbered ifn I can remember what it is, thought there was another name for it - anyone help? I seem to be going slightly senile