I am not a hundred percent sure that recovery speed really makes much difference in depth on the beach. Really depends on how fast you are swinging the coil and if you can hear the good thru the chattiness. Sensitivity allows bit more depth to go a bit further but at the cost of more noise from the salt and minerals, emi, etc. Iron Bias FE/FE2...I pretty much keep that stock now on the beach. I will dig everything that is a repeatable sound to it even if it is a whisper but repeatable (that is the deep stuff I love to hear especially on the wet sand).
I usually use Beach 1 with a 3 tone set up (<0/1-19/20>) with around 20-21 sensitivity but will switch to Beach 2 when swishing through the water or my ears need a rest.
Also depends on the coil...I use the 15" Minelab coil alot but found that I like using the 11" since it seems to pick up some very tiny stuff even at a decent depth in wet sand whereas I think the 15" is more for coverage and maybe a wee bit more depth at the cost of getting some of the very tiny targets (I have found some incredibly tiny metal things at 6-8in in wet sand with the 15" but more with the 11").