I had the same problem when I installed the HDSI transducer on my Crossover. I tried adjusting it a few times before just accepting that I was going to have to deal with it in some way. There are two ways to get around this. The first is to run a skimmer transducer (XNT 9 20 T) with a splitter going to your SI transducer. This will allow you to raise the SI transducer up so that it is out of the water when on plane. This option will also give you better bottom readings while on plane.
The next option is to make some sort of spray deflector shield which is what I ended up doing. I just made it out of a sheet of aluminum and attached it to the outside edge of the transducer board. Works well and really doesn’t look bad either. Definitely a cheaper solution.