This is all mix up.
Why to make so difficult simple stuff?
1k has larger particles then 4 k.
Now when you move your blade against larger particles , they will remove more metal in larger size and will leave larger scratches.
(Now we do assume they are made with same company and join with same glue etc) above statement should be correct.
Now can you set bevel with 4k of course you can i am sure you can set bevel with AN ESCHER but questions is how long it will take and how much stone you will loose.
1k advisable for straight razor because you do remove enough metal which easy set the bevel . Can you use 325 yes but result you are removing unnecessary metal. if you are sharpening axis i am sure i will say please go head use 100 grit stone.

i hope i didn't add more confusion.