15kg should be all you need on the bow.
I anchored hundreds of times in the Keys and the Bahamas
, never had a need for a second anchor...That was probably the olden days when folks used Danforth anchors that did not reset right away if twisted out of position.
60 feet of 5/16 HT chain and a hundred 3/4" nylon should do ya fine.
And of course a spare or 2 spare emergency
anchors stowed, but not too far away.