Hi Ian,
A couple of comments based on my Dad's experiences on an LCT-6 (544) in the fourth wave at Omaha. The gunners on his craft were exposed and firing the whole way in and suffered casualties as a result. You may want to show this on the LCM.
As the craft approached Fox Green, they were semaphored by a signalman from a knocked out LCT. My Dad was sent on top of the pilot house to read the message, which was, "Keep your heads down, its bad in here!" Naturally he was not pleased to be exposed with the MG whipping around.
The knocked out LCT had landed five tanks onto the beach, all of which were knocked out as they came ashore, and the crews were huddled behind the shingle wall on the beach.
The shingle wall was about 6 ft high at the high water mark, where most of the early survivors huddled. As a result, mortar fire was the real killer, the men were sheltered from direct MG and rifle fire.
My Dad's skipper decided not to land at Fox Green, since there was no-one else there except the wrecked LCT-5 and its destroyed tanks. He moved down to Easy Red where there were many more men, tanks and equipment, and landed there. His LCT carried a bulldozer with a sled full of matting (to get through the shingle wall) and a couple of recon jeeps from 5th Ranger Bn.
Hope this helps. I have some photos my Dad took at the time if you'd be interested.
Steve