I had a similar experience but problems with launching at Maraeitai, not retrieving... Launching the boat at low tide... I never tried beach launching with the Subaru Legacy AWD.. so I had the addage "whats the worse that can happen" and "if I dont do this ill never know"
Managed to get the back tyres sinking into the sand when reversing.. a thought poped into my mind.. "hang on... somethings up here".. got the boat off and the trailer unhitched... legacy wasnt going anywhere.. all 4 tyres stuck in the sand..
Lesson 1: Don't back in a straight line down the beach... approach the water at a 45 degree angle.. so you can drive across the beach rather than up it...
Luckily there were a few spectators chuckling while this was all happening so managed to get a few hands for a push... got the car out, trailer out by hand and boat in the water..
Being low tide only had less than knee deep water.. got into the boat and took off.. when I got to the ramp later on the fin on my new outboard was all worn

Lesson 2: Dont tilt the engine right down when operating in low waters
Retrieval was a breeze, again retrieving just after low tide, unhooked the trailer, pushed it into the water... tow rope around the trailer and the back of the legacy, pulled it out of the water.. No problems on the way out.
Needless to say I dont think a Legacy is up to scratch for beach launches, wheel diameter is just too small, road tyres dont cut it on the sand.. Retriving at low tide is no problem, but launching... I think ill wait till I have enough water on the concrete ramp..
Anyone think about doing it? heres a good article
Also, if you plan on doing it, do it during daylight hours, theres always some Samaritan willing to lend a hand.
Regrets? none.. just another lesson in life
