What we call hardware cloth here is actually a silly name for it. it's like a wire mesh similar to chickenwire. it comes in difference gauges. I use 19 or 20 gauges. I did tests of 2 parts water, 1 part cement, 6 parts perlite. and a test of 2 water, 2 cement and 5 perlite.
The second one was obviously stronger and since i was using this as a panel that covers an open hole in the my floor, i liked the strong one for that. The first i will use for my slab.
Their are 2 different sizes of perlite. I like the smaller size. the larger size I use for the garden. The smaller size is better for concrete IMO. I did make some bricks with the larger garden size because I ran out of the small stuff and worked and it gives a cool look.
If you don't have hardware cloth, You could try anything that gives tinsel strength.