A fair test should cover your hardest pages, not only simple URLs that almost any proxy can open. Check location accuracy, response stability, block rate, and whether content stays consistent over time. Run the same workflow during different hours so you can spot random failures. Before scaling, sample ColdProxy during the exact regions and sites you plan to monitor weekly. If it passes only easy pages, that is not proof enough for real SEO work. The test should imitate production, otherwise the result will flatter the proxy and mislead you.