This article gives us some useful numbers:

The mascons' gravitational anomaly is so great—half a percent—that it actually would be measurable to astronauts on the lunar surface. "If you were standing at the edge of one of the maria, a plumb bob would hang about a third of a degree off vertical, pointing toward the mascon," Konopliv says.

So the "water hill" would essentially be a plateau, hundreds of kilometers in diameter, with a slope of a third of a degree at the edges. It wouldn't be prominent enough to be noticeable, or distinguishable from the normal curvature of the Moon (where 1/3 degree is equivalent to 10 km).

Kicking satellites out of orbit seems impressive, but keep that this happens over time, after the satellites passes over the mascons many times and is nudged a tiny bit each time. And an orbit is a rather delicate thing. The local effects of a mascon are not really that impressive.

This article gives us some useful numbers:

The mascons' gravitational anomaly is so great—half a percent—that it actually would be measurable to astronauts on the lunar surface. "If you were standing at the edge of one of the maria, a plumb bob would hang about a third of a degree off vertical, pointing toward the mascon," Konopliv says.

So the "water hill" would essentially be a plateau, hundreds of kilometers in diameter, with a slope of a third of a degree at the edges. It wouldn't be prominent enough to be noticeable, or distinguishable from the normal curvature of the Moon (where 1/3 degree is equivalent to 10 km).

Kicking satellites out of orbit might seem impressive, but keep in mind that this happens over time, after the satellites passes over the mascons many times and is nudged a tiny bit each time. And an orbit is a rather delicate thing. The local effects of a mascon are not really that impressive.