had some interesting times with the STX Bridle - never liked it out of the box and tried JPC's dimensions also- again wasnt rapt in the result. My friend GrantC also has a 1.8 and he experimented and ended up with a different set of dimensions for the turbo, and applied them to my kite - I too prefer these settings.
GrantC's bridle dimensions:
From Upper Leading edge to turbo leg 45 cm
From Lower Leading edge to turbo leg 46 cm
turbo leg 8 cm
Spine to turbo leg 58 cm
The published spec for comparison:
From Upper Leading edge to turbo leg 45 cm
From Lower Leading edge to turbo leg 43.5 cm
turbo leg 6.5 cm
Spine to turbo leg 50 cm
and from JPC photo
From Upper Leading edge to turbo leg 47.5 cm
From Lower Leading edge to turbo leg 43.5 cm
turbo leg 7 cm
Spine to turbo leg 53 cm
Give it a try better precision no apparent loss in wind range or trickability