Thick/coarse ... like you, salt & pepper.
I read somewhere that the white hairs are quite a different constitution to the pigmented hairs and are somewhat stronger/thicker. I might be wrong, but I certainly feel like my shaving has had to change since the white came through.
I like sharp blades and I find blades will tail off quite quickly for me. Three shaves off any blade is usually enough. If I push for four, I will always regret it as regrowth will be irritable and prone to a few that stay under the surface and grow through unevenly. For the price of DE blades, you might as well chuck 'em after a couple of uses and not entertain their dying qualities.
I know there's some discussion that can be had around his method, but this chap at least did something actually scientific about trying to understand blade sharpness:
https://www.refinedshave.com/razor-blade-sharpness-summary/
What I read into his findings is that particularly GIllette are better on the second run (or certainly sharpen up during the first run). Their sharpness at the end of the first use is usually dramatically sharper than from new. If we look at sharpness from new, we're looking at: Feather, Gillette Nacet Stainless, BIC Chrome, PermaSharp Super & Personna Platinum (Israeli) as the sharpest; after one shave, it's: PermaSharp Super, Gillette 7 O'Clock Super Platinum (Black), BIC Chrome, Wilkinson Sword (German) & Gillette Nacet Stainless.
My preferred sharpest blades are: PermaSharp Super, Gillette 7 O'Clock Sharp Edge (Yellow), Silver Star Super Stainless Gillette London Bridge & Feather. That said, my favourite sharp AND smooth (all rounders) are: Treet Platinum, Rapira Platinum Lux, VOSKHOD, Lord Classic & Gillette
Super Blue.