There is so much I don't know about this game, its not funny.

Here is my situation: I'm going all-in on the Winged Spear, which is a Dex-biased weapon ("C" in dex, "D" in str, IIRC).

Should I be dumping all my offence stat points in to Dex then (apart from my investment in End)? Should I be blending Dex and Str?

As it stands, I have enough End to wear my knight's armour w/o the helm or gauntlets, my spear and sheild, and be able to do the less-than-half-equip-weight roll, so I don't have to worry about the 'fat roll'. I've reinforced the spear to +5, and need ember (I guess) to take it higher. I've put most of my other points into Dex, but my DPS isn't huge, so I'm Str-curious. Low DPS might just be the acceptable trade-off for my 'poke out from behind a shield' cautious style, but I wonder.

I'm going to re-roll on my real profile so I can get online and put the cheevos to my name, for good or ill, so I've got a chance to go back and make changes. Any recommendations of a more general sort for a light-knight maining the winged spear?

I believe you should put the minimum amount of STR to wield the weapon properly, and then just pump DEX all the way up. When you start upgrading that Winged Spear, unless you're going to do the magic, fire, or electricity upgrades, that C in DEX is going to get much higher.

Of course, I'm basing my opinion on what I know about Demon's Souls, but I'm fairly certain they work on the same principle. (Well, it what I'm doing with my scythe, so I hope so!)

That sounds like good information, thanks @RuneseekerMireille

I've got too much work for the next few days, but Cannuck Thanksgiving is this weekend, so I get Sunday and Monday off. Dark Souls and turkey, F'yeah!

Sounds like a plan! Good luck!