I really don't see the benefit in dumping points into other stats for minor increases and gimping yourself on your primary purpose just because there's an item that'll correct your "creativity" halfway through your experience. If you pumped CON up, you're still not going to be taking many hits as a Wizard, and you should be playing at maximum range anyway. Any of the other stats are going to be largely pointless outside of DEX for the added AC, but again, the goal is "no touchy." I feel like I need a thorough explanation as to why you'd make a character useless for 50% of your game until you get one specific item when the two logical attributes to distribute those "extra" points between are counter-intuitive to the playstyle of the class, lol.
Con is needed to maintain concentration checks and stop them getting disrupted when hit, it should always be maxed after INT on any Wizard. Dex and AC decrease the chance of getting hit, thus allowing you to not get concentration broken at all.
In this game, one of the Dwarf races has inherent medium armour proficiency and con +2, which means you can make a wizard with a high Con score of 17, also 15 dex, and actually while you still have points for 15 INT, you would only be able to raise 15 to 19 at level 8, which isnt any better than 18.
You can therefore have a Dwarf Wizard with 17 str, 18 con, 16 dex, 18 int at level 4 and wearing medium armour.
Currently you cannot reach 20 INT anyway so this is the best way to make a Wizard.
