Given your stated anchoring parameters, I would suggest the venerable Danforth 8-S.
I used one for the only anchor on our prior boat, a 4000# 26 footer, for ten years of summer cruising. We anchor in a sand/mud combo. It Never
is the chain. For a general "rule of thumb" go with a chain length equal to your boat length.
With a nylon three-strand rode, you should be OK. Since our '81 model boat did not have an anchor locker, the whole anchor setup lived in a sturdy mesh bag that we kept in a cockpit locker and carried forward for anchoring - not fun, but it worked for us.
There are probably quite a few "correct" answers to your inquiry... pick the one that meets the graphical intersection of confidence and acceptable inconvenience.
FWIW, on our prior boat, a 1550# Ranger 20, we used a similar size anchor setup, but did not anchor out often enough to really "test" it.
Our current boat is a 11K# 34 footer that uses a Danforth 13H. Same area and bottom compostion. Never dragged in over 15 summers. We have had to occasionally power it out (!) the morning we departed, though, from under an est. two feet of bury!