I would go with the heavier chain. It's not about strength, but weight and keeping that anchor horizontal. 1/4 in chain is not enough for ANY boat
. Well, - - perhaps your dinghy
. Have a set length, for me, 30ft, then a length of rode just short of the depth
so that it does not touch the bottom. Don't anchor in deeper than 30ft, so that you can dive the anchor out if it gets caught, and preferably around 10ft. Be sure to have anti-chafe on the bowroller.