Do you think the use of https://www.northernbrewer.com/products/brewers-crystals-1-lb would replicate the corn syrup?
Possibly? The trick is knowing what type of syrup the original used. Brewers corn syrup is produced to have any sugar profile desired, matching what would be produced using grits or flakes in different mash programs; that is, different ratios of fermentable and non fermentable sugar. The Schlitz sheets Denny has, for instance, specify a product called "Low Ferm," presumably a syrup high in dextrines and low in fermentability. Since those crystals contain glucose, they are probably more fermentable. If you want an actual brewers corn syrup, my LHBS sells it:
https://www.grapeandgranary.com/corn-syrup-25-lb-jar.html (You can even get a 60 lb drum if you're really going all in on this!) But again, no indication as to the carbohydrate profile and fermentability. I may not get around to brewing one of these until lawnmower season comes again, but my inclination is to simplify, use flaked maize alone for the full amount of adjunct, and mash to produce a wort you think is appropriately fermentable. Gives you full control, even though it's a matter of interpretation how that should be exercised.