Just an FYI. Here is some part numbers to order from weber. I am going the 18.5 WSM leg and heat shield route. Here is part numbers and prices.
18.5 WSM Heat shield is 63017 $15
18.5 WSM Leg kit is 63022 $22.70
Lid lock wire for 18.5 is 86824 $5
Lid lock support for 18.5 is 86821 $5
Hardware kit 80805 $5