Here is a $120 plate amp. 250w at 4 ohms, 156w at 8 ohms...

Dayton Audio SPA250 Plate Amp

I would need to build some sort of "box" for it, but that wouldn't be a problem I wouldn't think.

Thoughts on this one?

I would just wire up each set of 4 shakers to either 4 ohms or 16 ohms, and then take the two wire runs that go back to where the amp would be and wire them in series or parallel (depending on which way I went - 4 or 16 ohm each set) and get 8 ohms.

I just want to make sure that I am thinking right before ordering something.

Farewell - June 4, 2020