I really cannot recommend zoysia instead of St Augustine. Especially not if the St Augustine could not be kept. Zoysia is a high maintenance grass. Most homeowners are not willing to pay for correct maintenance and most service providers are not willing to maintain it correctly. Mowing is done with a reel at between 3/4-1". Rotary mowers leave an ugly cut. They also keep the grass too tall and thick, aggravating diseases. I suspect, the reason why I do not see much large patch is because zoysia is usually cut with a reel here. The ones not, do have dead patches in them. I have seen some Zenith zoysia lawns. I do not know how it will hold up under starvation fertility regimes combined with high humidity and rainfall. Dollar spot gets it good if 3/4 lb N and at least 1/2 lb of K per month of growing season are not part of the program. It also is dead if it does not get at least 6 hours of full sun per day.
They who can give up essential liberty to obtain a little temporary safety, deserve neither liberty nor safety.
Benjamin Franklin 1775
Sell not virtue to purchase wealth, nor Liberty to purchase power.
Benjamin Franklin Poor Richard's Almanac1738