could anyone recommend a progressive track that has nice strings or pads building stabs that made it big in sales ?
Wow alot dude, some of the vintage benz & md stuff made good use of chords, deadmau5 of course, Markus Schulz, Dousk etc lots more, check some them tracks out on beatport ro youtube, 
Opps, Pryda too!
any that spring t mind where the sidechained pad/string takes the lead ?