Having trouble getting dram in iMac slot

My cards are in the slots closer to the power-cord port. But I, too, am having a tough time removing either card, despite the video -- which, I notice, does NOT feature a generic #2 Phillips screwdriver. Yes, of course I lifted the tab out of the way. And I, too, have been the sole user of Apple Store-bought 27" mid-2011 iMac (apparently year's sole 27" model).

Close-up of video's screwdriver. Even the Apple Store manager insisted his techs said "ordinary #2 Phillips screwdriver", but using one barely fits, much less seating properly in the hole at 180 degrees. With standard #2 screwdriver, you need strong fine-motor skills, clear direct lighting and particular care. Or you'll strip the panheads, guaranteed. (Note: lousy idea in such configurations to fully unscrew one screw at a time. Lateral torque makes second and third screws "fight" you. Video should depict partial loosening of each screw, followed by full removals; wouldn't hurt if its limited text called for something besides "#2 Phillips screwdriver.")

Me, too. I finally got the panel off, but each tab just attaches to the outer edge of the metal partition between the slots on that side of the access panel's center screw-hole. I could pull each tab daily for a year, with zip for results. Meanwhile, along with having no press-to-release spring mechanism, both my factory-installed RAM cards seem to have been Super Glued (or soldered) in place. Even needle-nosed pliers can't budge either pre-installed 2GB card. What gives, Apple? How could unit's RAM be upgraded to officially maximum of 16GB, with original pair of 2GB cards in to stay? That would require adding a pair of 6GB cards in the two vacant slots; in mainstream SODIMMs, all I've seen are 2-, 4- and 8GB cards. Besides, I was told I had only three options: A) keep factory's 2GB cards, add 2GB card in each vacant slot (unit total 8GB); or B) keep factory's 2GB cards, add 4GB card in each vacant slot (unit total 12GB); or C) replace original pair of 2GB cards with 4GB cards, then add 4GB card to each vacant slot (unit total 16GB).

Does this Install Video help?

https://eshop.macsales.com/installvideos/imac_mid_2011_mem/

With the iMac face down, is it the top or bottom slots that are the problem?

Got a magnifying glass to take a good look?

Have you owned this Mac since new? What year, what model is it? In my experience the original RAM is installed in the bottom slots when the i-Mac is face down.