Okay, assuming you use the weights above (Stre:1 / Crit:0.74), you then just use those to work it out.

420 stre (x1) = 420

480 crit (x0.74) = 355.2

420+355.2 =

**775.2**
Or,

960 crit (x0.74) =

**710.4**
So, with the weights, you have basically worked out which one of the above (pure crit or socket bonuses) will be better. Bearing in mind one change of your gem will change those weights - which is why most people use a general weight and caps (haste breakpoints for example) instead.

side-note; heavy night + early morning, so mind any errors in my already fail math.