Thomas,
Thank you so much for taking the time to evaluate our current situation. Let me see if I can address some things that you brought up.
Have we moved to Shopify?
No. The stakeholders wanted a look and feel that of Amazon.com and McMasterCarr.com
Fix your robots.txt & make a sitemap index.
Robots.txt - I'm not sure what I need to fix in the file given your statement.
Sitemap Index - I made an index file and submitted that to google. But over time I found that single file more difficult to correct crawl errors. By creating individual sitemaps for the relevant part types I felt that was easier to manage. Is there a direct benefit from Google to have a single sitemap index covering the whole site? Am I getting penalized for doing sitemaps the way I am?
Rel="canonical"
You are correct that /spacer is being canonicalized by /spacers. That was my intent. I was under the impression that if multiple pages, of similar content, was serving the same purpose I should pick one and tell the engines to focus on that. When /spacers was created we thought that page really answered the questions that people tend to ask about our product. Thus the creation of /spacers and pointing heavily to it.
Meta Descriptions too long
Agreed. I'll have to figure out how to deal with that working along side the content writer. Programmatically it's fun because every page is template driven.
301 /spacer to /spacers
I'm not sure why that is. Could you explain to me the benefit of that? I don't want /spacer to go away and it hasn't moved. We haven't rebranded the site nor changed URLs.
I'm also up for a phone conversation if you'd like to continue that way.