The prototype test bed flew on just 160 hp and weighed about 2200 lbs loaded for a power to weight ratio of .082.

The intended production version had 3200 hp on 15,000 lbs load or a ratio of .213. That's alot better than many other fighter aircraft of the period had by quite a margin. But, since it never flew any real test flights we shall never know for sure.

Seaplanes, jet or prop, have some severe drawbacks. The biggest is the need for a planing hull and having the engines mounted such that they will not ingest water or spray. These problems along with the saltwater corrosion issue make them less than desirable in many applications.
The Zimmerman design built with a couple of turboprops of even greater power could even today provide a useful ground attack design. I would think that the aircraft itself could be made rather stealthy without undue difficulty and having the engines buried on the top of the "pancake" would make them less vulnerable to dust and fod ingestion while the exhaust in such a location would reduce the IR signature to ground fired missiles.

__________________
Truth is stranger than bullshit!