I might be able to help a little as I'm familiar with the make and model of that boat, I think? The Tahoe 1950 is an alum. deck boat, right? I just recently purchased a Lowe 2220, which is very similar but a little longer (same company I believe), for my latest project. The boats sit pretty low in the water - like many bass boats. I'm thinking the front deck is only 24" to maybe 30" high (tops) measured from the water surface.
I'm no trolling motor expert, so I don't know how they are measured, but it would seem to me that the 54" would be plenty long, unless you're planning on running a transducer or something like that on it, or you're going to be out in swells where the front of the boat may lift the trolling motor prop up out of the water as the boat crests each swell. -Al