PLEASE tell me those aren't compression fittings.... Compression fittings on brake lines are NOT a good thing. If you install a solenoid there, make sure you double-flare the lines.
Seriously, check out the PMP setup. They use Jeg's solenoids, mounted in the wheelwells on each side, and the kit comes with braided flex lines to insert the solenoid in between the body-side hard line and the flex line heading to the caliper.
If that compression fitting fails, it will do so under panic-stop conditions, where line pressures can spike upwards of 1000PSI, and if (when) it fails, you will lose braking on the front two wheels, where 80% of the stopping is done. If you want to run a single solenoid, I would screw the brake line into a flare-to-AN adapter right at the ABS computer, hit the solenoid with an AN fitting or a short braided hose, and then bounce out of the solenoid with an AN line or fitting directly into the ABS box. That, or mount the solenoid right next to the master cylinder, and run it inline there. I would, however, avoid compression fittings like the plague.
