Besmount transducer?
 

I have a cheap Lowarance X-4 ff, I also recently purchased the Lowarance scupper mount. But after installing, the transducer sticks out of scupper more than I anticipated. I know it will be a problem during transport. So now I'm back to square one

You could just stick it into a pool of sealant in the bottom of the bilge and tape it down until it sets. You'll have a bit more noise but I've heard this works pretty well.

You may want to take it to OEX and let them install it for you. Just sticking the transducer down without making sure that you have all of the bubles out of the marine goop may give you false and or inaccurate readings on your FF. Andy at OEX Sunset Beach has installed two FF's for me over the years and they end up working great, no problems, (though I did end up having a bad transducer and had to have it replaced).

When I talked to the Lowrance Service rep, he said that the transducer works best if it's in contact with the water.