It is designed to be tucked under shingles.
If you are buying from homedepot.com the box quantity is 50.
Yes, just push more under the shingles. It’s a good idea to overlap about 1-1.5” for strength at the joints. This requires notching the front edge at the overlap points. A little more work but well worth the effort.
Small material is what gets into my gutters despite these gutter covers. My issues is with pine needles and white birch seeds. Together a few needles and the small stick seeds collect inside the gutters at the downspouts so I need to clean my gutters twice a year. These gutters are the third type that I have tried and work the best. I have had these in place now for several years, cut to fit under shingle nailing, front edge attached to my gutters with gutter screws so that they do not blow off in high winds.
YOU CAN INSTALL THESE GUARDS AFTER REMOVING NAILS AND RAISING PANELS. The metal roof that was popular in the 1990's (in the Sacramento area) were from CalPac which were panels about 52" long by about 18". The edge of each panel was scalloped to fit into the curved recess of the panel below. The lowest panel would overlap the roof edge and slightly extend into the gutter which made slipping anything underneath the panel impossible unless the lowest nails were remove and the panel lifted (which is what I did for the 22 foot length of gutter above my garage door eave). The second row of panels hold the 1st row in place and it is not necessary to replace the nails which would be too short. Getting the nail out of the bottom panel when overlapped is tricky - use a screwdriver and fulcrum under the nail head. DO NOT ATTEMPT TO RAISE THE METAL PANELS ON THE GUTTERS SURROUNDING YOUR HOUSE UNLESS YOU HAVE SHEATHING UNDER THE OLD SHINGLES (AND NOT 4" WIDTH SLATS WITH SPACING AS MINE ARE WHICH ALLOWS UNDESIRABLE CREATURES TO SQUEESE INTO YOUR ATTIC SINCE THE OLD SHINGLES ARE ROTTEN). THIS WAS THE METHOD OF CALPAC TO ROOF OVER THE OLD ROOF (SAVED ON COST BUT INCREASED LONG TERM GRIEF FOR SOME). I WAS ABLE TO DO THE 22 FEET OF GUTTER GUARDS WITHOUT GETTING ON THE ROOF USING A LADDER (STAY OFF METAL ROOFS UNLESS YOU KNOW HOW TO WALK ON THEM WITHOU DENTING). IF YOU NEED ADDITIONAL INCOME (I'M TALKING ABOUT A JOB HERE) - THIS WOULD BE A GOOD START. LOOK AROUND YOUR NEIGHBORHOOD FOR THIS TYPE OF ROOF AND ASK THE OWNER IF THEY WOULD LIKE TO HAVE GUTTER GUARDS INSTALLED- STAY OFF THEIR ROOF AND YOU CAN'T BE ACCUSED OF DOING DAMAGE- DO ALL WORK FROM A LADDER. SINCE I HELPED YOU FIND A JOB YOU CAN REPAY ME BY CONTRIBUTING TO THE WILD FIRE REBUILDING IN PHOENIX, OREGON. And by the way buy the Gutter Guards from Homedepot.
This is the first winter and so far they are doing great with no problems.
I attached them to metal gutters, probably another brand. I didn't install the gutters, just the covers. They snapped on, but I screwed them down with sheet metal screws, one on each end (my guess is they would hold through a pretty strong wind without being screwed down). I would also guess that they would also snap on to Amerimax vinyl, since same brand and material. 5" sounds about right for a good fit. they worked on the house, but the gutters on the (separate) garage were too narrow, causing the covers to curve into a shallow U shape, thus retaining the rainwater and overflowing back under the shingles. So I had to remove the covers from the garage gutters, which are also metal, I think are about 4".
I am not aware of any "connectors" that are available for this product but because they are thin enough they can simply be overlapped as is recommended in the installation instructions. The Installation instructions say to overlap them 1 and 1/2 inches and to do you have to cut back the portion that attaches to the gutter. This was the only suggestion that we might make to Amerimax; that they should come with a factory cutback of a 3/4 inch at each end leaving an attachment between the gutter cover bull-nose and the portion attaching to the gutter while giving you the ability to still overlap the recommended 1 and 1/2 inches and allowing you to work in either direction when installing these gutter covers.