Re: Bridge Maintenance
Personally I wouldn't use that, as I'd be concerned about any effect it might have on the guitars finish. Also being a spray it could get anywhere, and I wouldn't want it seeping into wood, or under any lacquer.
You don't say what adjustments you've made, or the age of the guitar/tuners. If its just since you've changed things; have you done something to change the string's pull or its position, that might interfere with smooth turning. If your tuners are new they may have worn, and there could be some muck in there. If they're older they might have picked up gunk over the years, in either case you may want to take them apart for a clean. Whilst apart, and away from the guitar, I would get the WD40 out, as its a good cleaner (just make sure you've wiped them well before putting them back on your guitar).
If you just want a lubricant, personally I'd use a light oil, a light sowing machine oil if you can get it, but nothing no heaver than 3-in-1.