I've always been very wary of putting any kind of lubricant on screws, if the threads are tight the best to use is usually lighter fluid or plusgaz (a uk thing for loosening screws) but they are so thin even a soaked cotton bud can have enough to let it run who knows where!!!
The two best tips I can give are:
1)
Get some good jewellers screw drivers. the best way not to bur the screw head is make sure the screw driver fits it spot on, and most jewellers screw drivers handle differently as the are made for this small scale work so you will find them easier straight away.
2)
If the screw looks corroded or it wont loosen because it has seized with age, try gently doing it up a tiny bit, this will usually be easier, and it will break the corrosion which will then let you undo it much more freely.
Let me know how you get on...