I'm also thinking of going with Tacktick instruments to replace our faulty depth instrument (a 20 year old Navico system). I was ideally wanting to fit a mushroom shaped sounder as it would fit into the existing faired position in the hull and contacted Tacktick to ask if other instruments would work. They replied to say:
"The T121 Hull transmitter is compatible with most Airmar transducers speed
and depth. The Depth Frequency must be 200 KHz and the speed a voltage
pulsed with 3 wire or 5 wire including sea temperature."
Though as a word of caution they did suggest that I confirm the relevant part number with them first if possible.
I was interested to hear that the wind display is clear as I was concerned that an LCD wind display might be less user friendly than the traditional mechanical needle perhaps owing to the screen smearing when the 'needle' moves (much as some older LCD monitors are prone to do).