1) Gets smaller at night, but only closes fully up once in a while -- every other mouth or so -- assuming I don't "bug" it.
2) Feed it about every 10-14 days, either krill or sliversides (( or when I remember
))
3) No issue with hermits or nass snails
4) On my 58 gallon tank 2*175 MH + 2+96 PC MH one for 8 hours a day, PCs 10
The above answers apply to me and experiences with my LTA in that tank.