Yes, I agree with Spaugh insofar as Sweet Tart is a great-tasting mano.
I have two tweet tart trees growing at two different locations, both grafted on Manila. The 1st in Alhambra (Very inland and hot) grows and produces well with quality fruit. The 2nd grafted tree on Manila rootstock in the SoCal Coastal Zone in my location in 92647 grows moderately vigorously but has issues with pollination, Powdery mildew in spring and into early summer. The cooler coastal temperatures have a negative effect on the sweet start of Flowering and fruit formation. My tree has overall been disappointing in terms of fruit production for the last several years.
Location, Location is the key. Sweet Tart prefers warmer inland locations. Just my experience and two cents.
Johnny