Have a look at the link below there was a very comprehensive write up on here a few years ago where one was wetfaced through the hull, a bit of work but a great result.

http://fishwrecked.com/forum/cruise-craft-575-585-thru-hull-50b-9b-transducer-install

You can transom mount them also, Fibrelite boats in Oconnor make a mould that fits to a standard tm260 furuno transom mount bracket.... they also make the below transom mounts up

https://www.boatsonline.com.au/boats-for-sale/used/marine-items/200b-8b-tm-transom-mount-transducer-and-fairing-package/217771

You could get an ali bracket made up and recess the transducer lip into it as these are a tank mount transducer and transom mount that. A good welder can fair in from the hull surface to the level of the transducer. Theres a good group on facebook with examples of these called "Boating Electronics. Help Discussion Settings Information" that has examples of this style of mount

Great transducers and you will be happy with them. Any reason why you arent going 2 or 3kw with the 50khz side? Would be a good combo on the 295 and utilize its deep capabilities better.

 Thanks for the response I think I have an idea now...