It was like a year old, but I used a comment extractor software. I think it came with Ultimate Wordpress Comment Spammer (UWCS). It included a handful of tools. It had a harvester in one, another was a comment scraper. I remember I scraped a list of like 20k comments with it. I am not sure if UWCS was shared here or what.
Get a mass list of comments. Manually go through them line by line and think to yourself "can I make this comment work?". Get a nice amount of comments. The more the better. I would shoot for 50, remember you need to spin them too. So really you could have like 5k comment variations. This should get you by for a while.
It may require you sitting down for an hour to do this, but once done you won't have to worry about your comments for a while.