I open up Incognito mode and my regular chrome browser. I then open all 8 Amazon products in the regular chrome browser and take a screen shot using the snipping tool. I label them A114 (for the date) through A814.
I have a sheet of paper marked A1, 2, 3, etc through 8 beside me. I then add all 8 to my cart to see the earliest possible dates of delivery and if Prime eligible. I mark Y/N on my sheet of paper and note the price of the product and dates.
I then go to incognito mode and paste in the exact title into Walmart to see if they even carry the item before I start searching fruitlessly. If they do, I screen shot and save it in a similar manner as W114 to W814. I also have a column on my sheet of paper that shows the price and if 2 day delivery is available and make notes on that. Once that is complete, I go back into regular mode and begin typing in how I would look for the products on Walmart's webpage. If they didn't have it, I use terms anyway just to be double sure and of course, the last search is almost verbatim the title if it hasn't came up.
It knocks out a huge chunk of time. It isn't exactly the way they describe to do it -- open up an Amazon page, screen shot, add to cart, find Prime, then open up Walmart, start typing 6 things, find it, do the same but it does completely do the same process and it cuts out a lot of time due to copy paste and knowing if the actual product is sold by Walmart or not.