Upper control arm ball joint spindles not long enough on disc brake conversion

So I can't afford new later model upper arms, but from that kit DoctorDiff had in the thread hemi71 posted it comes with flange nuts instead of castle nuts. If I loctite those flange nuts and torque them down would that be safe as using castle nuts? Am I being paranoid? Does anyone have any experience using that kit instead of switching to newer arms? Thanks yall.