Dont touch spr, with the possible exception of going 125 for specific pvp purposes on otherwise full con builds, but its not even meta to raise it for pvp builds like that, just something that has a mechanical justification to it.
Full con is viable for a wizard. Int will raise your damage output quite significantly when you factor in bonus points, class rank int multiplier, skill attributes, and quick cast bonus if you are a wiz3
At low levels of course you arent getting many bonus points yet since nothing is high enough for it, you probably dont have very high attribute bonuses, and you arent getting full class rank multipliers yet.
At low levels you should raise your con first to where you want it, then start investing in int.
You should shoot for 60 con or so early on, and then raise it to 100-120 or so for the current level cap, depending on the equipment you choose to use.