The hand american is probably the best for a spray. I would start with 1 micron and if you want to take it a step further the 0.5 micron. I got both since I was already paying for shipping and it's not that expensive for something that will last a long time.
Do you have a website for the kind you found a source for? Who knows, it may be great. If it isn't that expensive maybe try it out and let us know what you think. Do you know anything about it like carat weight, is it monocrystaline, do they have any guarantee on particle size?
Edit: I found the website and the HA is quite a bit cheaper. You can get 12 carats for about the price of their 'economy' spray which is only 6 carats.