First,put some grease(any kind will do)into the bottom of the troughs,about an inch either side of the centre of the troughs.Then put either a couple of offcuts of 1/8" cork(the thickness of the 2 side strips)or some washers equal to 1/8" on each side of the block.Then put the sump back on(assuming you have the block head face down),and turn the crankshaft in the opposite direction of normal running rotation,remove the sump and measure the depth of the groove cut in the grease in the troughs by the dippers.
If the depth of the groove marked by the dippers in the grease is too shallow,the carefully bend the troughs upward,and try it again until you get the depth right.