Overlube. Don't listen to what all the pro keeb teachers tell you. Overlube (don't be afraid to use a generous amount). I've spent this whole time following their advice and being very gentle with the lube. Then my switches come out sounding scratchy. So then I say to myself, screw it, and brush a generous amount of lube on them. Lo and behold they're less scratchy, and they haven't become any more sluggish. I think ppl stress too much this "less is more" concept in lubing. Ultimately you'll have to experiment for yourself as this is my opinion, and maybe what I consider to be a lot others might consider just normal. Ofcourse use proper technique with applying an even coating with a brush, but I say don't be afraid to provide a generous healthy coating!
Edit: To actually give an objective observation, what I did was apply literally a double coating of what I normally apply to the stems of my switches. I then compared my single coated switches to my double coated switches. To be honest, many of them still felt the same in terms of scratchiness with the single and double, however there were some stragglers with the single coat that were definitely more scratchy, and overall the double coat feel slightly less scratchy. So it's a safer bet in my opinion to be more aggressive in lubing. There was no sluggishness in the double coated ones compared to the single coated. And I was using very light springs (the gateron clears at only 35g)!
Unfortunately I'm currently doing this experiment with silenced switches, so I can't make strong sound difference observations. They sound the same for silenced is all I can say.