What weight oil to use in my CL

I typically use 5-30 Mobil One in my CLs...My thought is a lighter weight like a 5-20 might free a few ponies but I do not want to do so at the expense of less protection....I live in South Florida and would appreciate any thoughts concerning the use of 5-20 weight in this area..

I have heard that Royal Purple is the best that money can buy. Would it be worth the extra $$ to upgrade from Mobil One??