How to boost security on tilt windows?

Please bear with me - it's a hard problem to describe, especially for
someone who knows little about window design.

Am currently in the market for sliding window locks for my new home (rental
duplex).   Sure, there seem to be hundreds of different ones on the market,
but I can't find EXACTLY what I need (and what will fit).

Specifics: I have several General Aluminum *high performance* tilt windows
in the new place, and am looking for a screw-on window lock that will not
only prevent up-down travel, but will also prevent the window from being
popped open by a hard blow to the (inadequate to my eyes) plastic sliding
locks in the upper corners.

The basic hex-key-at-a-30-degree-angle-design lock fits poorly, and the
design of the GA's L-shaped channel prevents the lock from fully contacting
the frame when tightening down the hex-screw, tightening down at an angle
inconsistent with the design...  OK up-down protection, but no *pop-open*
security.

But ... if I could find similarly designed locks where the hex-screw
contacts the window frame perpendicularly instead of at an angle, I could
perhaps clamp in an angle bracket flush with the corner of the window and
prevent pop-outs... but these types of locks don't seem to exist.    The
commonly available non-marring wingnut-screw design would work in theory,
except that its' tiny jaws will won't fit over the GA's 1/4" lip let alone
handle the extra bracket.   A hex-key design would also have to have a wider
jaw as well - they all seem to be 1/4".

Anybody know:

Where can I find (or cheaply engineer) the kind of lock I need?

or...

How do people make these types of windows secure, anyway.?   The basic
design seems totally geared toward the clean-freak housewife at the expense
of any real security.

Thanks,

Uncle D.L.