getting a matt finish in a tumbler

[daisychain]

So many of my current made-to-order pieces have a matt finish, and it is getting very time consuming getting an even matt finish by hand! I'm thinking of getting either these Ceramic Pyramid Chips, 6mm - 1kg - Cooksongold.com (http://www.cooksongold.com/Jewellery-Tools/Ceramic-Pyramid-Chips,-6mm---1kg-prcode-998-006)
or these Cutting Cones - 1kg - Cooksongold.com (http://www.cooksongold.com/Jewellery-Tools/Cutting-Cones---1kg-prcode-998-004)

but I'm not sure which. Does any one have any experience of either of them please?
I know whichever I decide to get I'll also need this Cutting Powder - 1kg, Un3262 I Tnt - Cooksongold.com (http://www.cooksongold.com/Jewellery-Tools/Cutting-Powder---1kg,-Un3262-I-Tnt-prcode-998-005)

I'm planning on getting them while the free postage is on this weekend!

Thanks!