Transducer depth and type

Hey guys,

A couple of very rookie questions here. I picked up my first boat about a year and a half ago. It's a "mud boat" with a surface drive mud motor for duck hunting but set up well for fishing too. I'm slowly building it up, so i'm looking at a fishfinder now so I can fish more than just my old faithful river spots. Wanting to get into shooting docks on the lake like I grew up doing.

Anyway, the long and short of it is I can't permanently mount the transducer on the stern without risk of totally ripping it off when I go over logs, through thick vegetation etc. My boat builder can make me a removable apparatus for the transducer (similar to the 'da ducer) but i don't know if it matters how deep the transducer sits under the surface of the water. Second off, can I use the stock transom mount ducer on this device or do I need the trolling motor compatible one? I think the only difference there is the mount but I feel like i've also heard they have some sort of extra "thingy" to reduce electrical interference from the TM. The mount will be on the front of the boat just across the bow from the TM. To be clear, i'm hesitant to just put it on the TM because I want to be able to scan without my trolling motor in the water, and I've heard that sidescan can get a skewed image unless the TM is totally straight all the time.

I did some searching and it seems like most units have some sort of adjustable offset in the menu to account for the depth? Likely looking at buying the Lowrance Elite Ti2 if that helps.

Thanks for the understanding and advice gents.

SJ92