I also searched for information on this a while back and found very little useful information. The best I found was a blog-style trip report which was moderately helpful at:
https://www.gang-gang.net/nomad/tasmania/tas06.htmlThat trip report includes a day-by-day report of each stage of the walk.
Since then, I've walked most of it as an overnight walk and a day walk (well, technically, I overnighted on the day walk too, but it was not necessary). I have not done the section from Eddystone to Ansons, but have done Ansons (Policemens Pt) to Gardens, and Gardens to Binnalong (well, to Jenneret Beach).
As you say, it's mostly beach walking, with some solid granite sections. There are a couple of sections just North of the Gardens where it is all small-to-moderate sized rocks, and they are a bit awkward to walk on (called "Pebbly Beach", but I would call them rocks, not pebbles!).
Most of the Granite sections are easy to cross. On a couple of them, you need to head into the bush behind the granite, in which case, there are some vague pads that you can follow. There are also some vague pads that you can follow that are just totally wrong, and harder to bash through than it would be to just walk over the granite.
The beaches and granite coastline are beautiful, and well worth the trip.