Yes, on the thinner oil and see what you get.
I have been told by a very experienced machinist that synthetics don't cling to parts long term so on a hobby type car that sits a lot you may end up with cam lobes that have less oil film on them. True or not I don't know for sure...… This guy has a 7 second drag car and he uses conventional oil in it.
I take it a step further and run STP oil treatment. Stuff sticks to all internal parts of the engine. Every one I have torn down has a sticky film all over everything. Hell of a lot cheaper than a prelube oiling system and good insurance for the cars that are not used every day in my opinion.
