I would think schools with tighter GC connections are going to produce a higher quality LOR. My D’s private HS had the college GCs start working with their assigned students freshman year. The college counselors were also different than the team that did regularly counseling and course scheduling. By junior year, D knew her college counselor very well. They also had students fill out a 15 page “get to know me” type survey. We, the parents, had multiple meetings with the counselor including one on one visits during junior and senior year. There was a lot of actual guidance and review of the college list to be sure it was balanced. GCs also came to school events, sports, shows, and were very engaged in school life.
In contrast, our home public’s GC had over 100 students each and didn’t do any of the above. Students met with their counselor once in 4 years. I have to believe there would be a difference in quality and depth of the LOR.