Will 3/4” pex with an inside diameter of .68 inches have enough capacity to supply a 3/4” manifold with 1/2” supply lines to a bathtub, washer and toilet and sink with no pressure drop? I plan on running 3/4” pex from water meter to the house. Once inside the house the 3/4” will branch off using a 3/4” Tee. The (1) 3/4 supply line will run to a hot water heater then as hot water leaves the heater from a 3/4 supply to a hot water manifold with dedicated 1/2 supply lines to each fixture. The second 3/4” from the tee joint will deliver cold water will also run to a manifold. Every fixture will have its own dedicated 1/2” supply. The outdoor faucets will have dedicated 1/2” supply lines as well.
It depends how many things you intend to use at the same time. Water pressure drops the more things you're using at once. I can run two hoses off a 1" line at once, but I lose about 75% of the water pressure.
If you're running only one thing at a time you should be just fine. If you need two it will be iffy, and I doubt you could do three.
Home run system is very good option. 3/4 supply is good for most houses. If you have low pressure with taps on 3/4 may be small. If you have big house with many lavatories and people 3/4 may be small. I think the easiest way to check is put a gauge at your meter. Check pressure with system closed. Open many taps. If pressure goes way down 25 to 50 percent bigger pipe will not help. You might need bigger meter before bigger pipe makes sense.