dropping my truck

[canadian 4x4]

I have an 85 swb Chev. i am looking at a 5/7 drop. my truck has 275/60/15 tires all around. i want to keep the 15" rallies. i assume these tires are to big for the front end. what size tire is recommended? i have heard you have to trim the lca to keep the 15' rim, this is fine. does anyone have a pic of how much has to be trimmed? which brand kit is preferred? is a 2.5 spindle 2.5 shock a better set up than a 3 in spindle 2" spring? i have read that 3" springs are not recommended due to ride, so i will stay away from those. any more info or opinions from people who have 5/7 drops is appreciated. if there is any other major complications with this setup? this truck is a weekend cruiser.