The main difference is that 5w20 is thinner at operating temperatures than 5w30. They both have similar cold flow ability.
I would use a synthetic 20/50 motor oil
Basically, the only difference between HD-46 and HD-68 hydraulic oils is the weight of the product. HD-46 is a 15 weight oil, but HD-68 is a 20 weight oil.
It can causes serious damage
The difference between 110% and 20% is 138.4615%
5w20 is a little thinner at operating temps than 5w30
There could be damage if you run a thinner oil then recommended, especially in the hotter months. If the motor calls for 5w-20, I wouldn't put in 0w-20 if I needed more than 1 quart. It would better to put in 10w-20 in a pinch, thicker viscosity oil can handle higher loads/heat but lower your mpg due to more oil pumping effort.
5w-20 of any synthetic motor oil brand.
The motor oil that is recommended for a 1996 Honda Civic automatic is 5w 20. This motor oil can be purchased at any auto parts store.
SAE 5W-20 motor oil is a multiviscosity or " all weather " graded oil that provides a wider temperature range of use , and permits you to drive from one climate extreme to another ( My Quaker State motor oil book sure comes in handy ) On newer vehicles the manufacturer may require you to use a 5W-20 oil in your engine - check your owner's manual (Helpfull)
20-50 motor oil
The recommended oil is SAE 5W-20