It is very important to try to drive your car on a regular basis.
Most of the time I get out the car I use for touring, it is usually for a drive of at least 10 miles or more one way and a lot of the time it is for more than that. I use a thermostat and get the engine up to operating temperature for a period of time. This helps keep all the moisture out of the oil which is very harmful to the engine.
I have a babbet "B" engine and I often use the car for long distance touring. I like a multi grade oil which is a little thicker than some like to run. Also, it gets hot in California in the summer. That is why I use 10-40 (winter) or 20-50 for long tours in the summer.
It is true that we do not really need zinc in the oil as we are running steel cams and the valve spring pressure in a Model A is not very high. Oil in the 30's did not contain zinc. It was not until the late 1940's that zinc was added to oil for passenger cars. This was with the introduction of the Kettering Engines from GM, Cadillac and Olds, OHV engines that operated at higher RPM and had higher valve spring pressures then was commonly used before this.
I gave up on trying to tell folks that Zinc was not really necessary for a stock Model A. Zinc is absolutely necessary for most OHV flat tappet engines to protect the cam from scuffing. Zinc will not harm a Model A engine and most people seem to think it is necessary for all old engines so I just leave it there.
Rotella is good as well as a lot of other oils. I just do not feel it is worth the cost to use synthetic oils. Also, they are usually thinner and tend to leak more. I do not like to run oil specifically formulated for Racing. Racing oil does not contain the anti corrosive agents and other additives "street" oils have. Remember, todays oils are all much better than what was available when our cars were new.
Drive your car on a regular basis, get it up to temperature. Use a thermostat to help keep condensation to a minimum.
This is JUST MY OPINION, and once again, I am sure others will have different opinions, which is fine with me.
Chris W.