RE:what kid of flies for monamoy
Nate gives good advice, I would add that there is a difference between fishing flats and fishing dropoffs and trenches. IN one situation you'll fish clear intermediates; in the other QD 325 grain sinking lines.
For flats work, sand eel patterns should include subtle ones in the 2.5-4.5 inch size, in other words sparse or translucent materials with not more than a strand or two of flash laid into the body and the color choices kept subdued.
Crabs are a great option. Contrary to popular opinion, the olive green felt works very well... per my firsthand experience. I also use sand colored / tan and brown crabs in craft felt. They don't need to be very large to get big fish interested. I prefer crab flies that can be easily worked along the bottom w/ hook point riding up.
Shrimp, small flounder, etc. are good options. Crazy charlies tied with sand colored materials; shrimpy patterns and patterns that appear to disappear into the sand with pronounced dumbell eyes do a good job imitating small flounder.
Even when fish were at their fussiest, I've been them root up sand eels and devour them as they leap from the water right in front of me. It pays to have something that works right into their feeding and hunting style on the flats. It's less the fly than the impression the fly makes on the fish... you hear the most incredible stories from people holding up scrappy nothing flies torn to threads by blues or numerous schoolies until what's left becomes the fly that tames the big flats beast.
Member Brian Lencho from Seattle got a nice bass on a squid fly last year on a picky mid-afternoon flat when it seemed other flies were of no interest to the fish.
<b>Drop-offs on South Beach, deep channels on North Monomoy...</b>
Off the drop offs at South Beach, every dropping tide has produced some big breaking fish. Sometimes they even come close to enough to shore... when they do, they are large fish and people get keepers on flies. This happened at the clave and it happened the last two times I tried South Beach since then. The hot color for fishing the drop off along South Beach was yellow, don't ask me why. I'd feel good about chartreuse or any visible color in this situation. Blues are common here this time of year, I lost some flies to chopper teeth Friday.
Bigger fish have been caught out on the ocean side of South Beach lately, so don't leave out the big surf patterns. This is Nauset to Race Pt. style widow-maker wave fishing, but you know that big fish love that thundering wash. Bring a few bright clousers and big fish flies for the surf if you plan on hitting it.
Hope this helps...