Johnson HT-2011 hyd lifters

Well I just got off the phone with them and they said I my have hylift lifters. but that all there lifters have a retainer on them so I am going to try and put clips in these as it just dosent make sense to me that the parts are free to fall out. and how would you set lifter preload if using adjustable rocker arms if the pistons were not all at the same height.