RHB: Daryl's idea has merit on a lot of points. Not sure if you can wheelweights but maybe linotype metal or plumbing lead, etc.?

A very simple handloading kit might do you well. Can you obtain powder? For example, during the time I spent in Zaire/Congo smokeless powder was unobtainable but blackpowder was available for some reason, and a fair number of folks used it to handload muzzle loaders. Blackpowder might be easier/safer and still very effective to work loads up with if you have a hodgepodge of components, too.

I really wish I had some of these slugs to test in my media. I'd be curious to compare them with some rifle cartridges and other "known winners" and you might have a good idea thereby what would work. Dry magazines are very hard on softslugs and unless you have some other caliber to compare to, you might be unimpressed with the results.

Obviously you could just use these things on game and observe the results, or if you have a good pig rifle or other good Brenneke loads, etc to compare with, shoot them into the same medium and compare with the Mirage slugs. Shot into a dirt bank, our 1 oz Fosters look like a donut, flat with a hole in the center. Comparing with rounds you know work well is the best way to use terminal testing media.