Heavier jigs fish 'faster' than lighter jigs. the heavier the jig the harder you can pound them because they fall really fast. light spoons tend to flutter down but these jigs are up and down really fast. also for deep water you can get them down ASAP and when they hit the bottom they make a thud which can attract fish. I use the 35 mm one for everything and it works well, especially deep water. They present a larger profile too so its more appealing to bigger fish. but if you have a stiffer rod you can pound these jigs really aggresively because of the extra weight.