Setting scale length on an ST

Hi,

Can someone advise me on the best way to set up the scale length on my ST kit.

I've already drilled and dry built the neck to the body, which I'm not sure was the right thing to do.

I know scale length is 2 x the distance to the saddle from the 12th fret to the nut, but I've seen some saddles offset to compensate for the different string gauge and its this part I'm not clear on. How is this angle calculated?

Any advice would be much appreciated

Thanks