Don't set the saddles in mid-position. That is incorrect advice taht still seems to be floating around. Set the top E/B saddle so there's about 2-3mm of thread poking out the end. Then measure the scale length from the board side of the top E saddle to the middle of the top E saddle slot. The top E string will always be the string nearest the nominal scale length, but will still need the saddle moved back form that by between 1-2mm when intonated.

That will allow you to correctly intonate the saddles later on, without the saddles being very close to the rear of the bridge, with very compressed springs and the adjustment screws poking up in the air.

I can't guarantee that you still won't have to do a bit of cavity enlargement, but if that doesn't do it completely, then it will get you a lot closer, with minimal work.

As sonic says, Teles should have a small gap between the bridge plate and the pickguard, though the control plate butts right up against the pickguard cut-out.