It is easy to find information, but you need to know what you're looking for. You may find economic theory, you may find criticism of that theory, or support for that theory, and you can even make conclusions, and I'm not trying to offend you, but I don't think you're knowledgeable enough in Economics to make any conclusions.
But that doesn't have to matter, because looking at just Supply Side is not enough. Look at what was happening before Reagan took office. Look at the Carter administration. Hyperinflation, skyrocketing unemployment, spike in violent crime, oil crisis. All of this went away with Reagan. The 80s was a decade of utmost prosperity, growth, and opulence. That's why after a hard win in 1980, Regan was re-elected by the biggest margin, winning 49 out of 50 States. The middle class, which you erroneously claim was squeezed, actually got the biggest boost. I encourage you to show me a single indicator to support your claim that it was "squeezed". It isn't MY definitions of success you need to be concerned but actual indicators that exist in any type of economic system you ever study. I suggest you erase your preconceived notions, and start studying economics from the basics.