[@Vertigo] Yes! Will need some minor edits just so it isn't game-breaking. While I know this is a canon character, and I personally won't be taking these rankings TOO seriously myself, having everything be ABABABABAB, can be tricky.

Charisma should be much lower than B, especially if he doesn't use it often. You've said it focuses on hunting giant beasts, so make Charisma C-D, or even get rid of it. Up to you.

As for his parameters, just mixing and matching from different canon examples would be preferable. Right now he's kind of a master of everything? Which I get it, he's a staple of the series, but everyone needs to be equal irp! Feel free to contest my suggestion but I would say:

Strength: B+ (A plus modifier against beasts, since that is his forte) 
Endurance: A
Agility: C

This Arthur focuses on hunting beasts from what I can gather, so being fast and strong is necessary and fitting of his lore but you can't be good at everything! Having C-Rank agility balances out the physical stats a bit. 

Mana: B
Luck: D

Emiya's Saber had D luck, I know it is a different version but I think that rounds the kit out a bit.