I think you're asking me how I kept the rail joiners I soldered on to the thinned PCB tie in gauge, correct?
How I make these bridles is...
I stripped the about 3" of ties off one end of about an 8" piece of flex track. I slid a code 70 rail joiner on each rail then laid them on the thinned PCB tie. I then placed a "rollee holder" from Railway Engineering on the rail heads to ensure the rails and the joiners stayed in gauge while I soldered them to the thinned PCB tie. I then slide the completed bridle off the flex track and place the bridle, joiner side down, on my desktop and trim the excess joiner with a razor saw. I tried trimming them with a dremel and a cutoff wheel, but the heat generated by the cutoff wheel was often enough to melt the solder joint. I then cut any excess "bridle bar" from the outside of the rail joiners and clean up and shape with a file. Cutting the rail joiners is going to leave them clogged with a little flash and perhaps a little squished. I clean up the flash and if necessary open up the joiner a little with the tip of an Exacto blade. When I have enough for one switch (usually 4 or 5) I slide them on the approach rails leaving two ties between each bridle. If the approach rails are coming off another switch you have to be able to lift the feeding switch up enough to slide the bridles on, if you bend the rails up enough to slide them on the rails and over the ties, you may bend the rails enough that there will be some vertical misalignment between the approach rail and the stub rails of the switch.(ask me how I know) The picture below illustrates this.
Here at least one route of each switch forms the approach rails of the next so switch 1 has to have the bridles installed on the approach rails for switch 2 before switch 2 is laid down, switch 2 has to have the bridles installed on the approach rails for switch 3 before switch 3 is installed and so on.