From today's outing I realized that the F5 with an 11" DD coli is a very capable detector that can find even the tiniest pieces of foil. Dang, they were so small that the propointer almost did not go off at all even when I pressed the probe against them! The F5, on the other hand, happily picked them up in 3-5" deep sand. Another thing was that I could run it full throttle, something I can not do at home. I had the gain at max, the threshold at max, and ran it in disc mode to cut out iron. I had very close to zero chatter! If I got an iffy signal, I just turned down the disc to 2 or 3 and got the iron grunt that told me I was over some old iron that had just rusted away.
I also learned that the F5 do not like wet salty sand at all. I know, it is written all over. Today I tried it myself.

Staying on the reasonably dry sand did work, though. Because after about 2½ hours I struck my first silver!

Not an old coin at all, but still. Silver! <:-P
I also found about a gazillion of old pulltabs, some reasonably new coins, a toy car, a tent peg, and some other lose bits n ends. Spent about 5 hours on the beach, and had a great day!