I found card protectors that are the right size for Dust unit data cards in my local arts and crafts shop. They are clear plastic sleeves, 15 x 10 cm. I found them with the ziplock bags and similar items. I think that people use them to store small bits and pieces, or package things they have made (for sale at markets or whatever).

15 x 10cm is almost an exact fit for the Dust cards. Actually, a very tight fit, because I had to bend each card slightly to slide it into the sleeve. (They have flattend out, since then!) Now, I do believe that Dust sell card protectors on their website, and those ones are probably more hard wearing than these, probably like the card protectors people use for Magic and other games. But, the main feature of the ones I use are price: $2 for a pack of 10. Bargain!

The official ones are $7 for 50 including shipping, so are actually even cheaper than the ones you found.

Still, it's cool that you came across some that size - that would be pretty rare I'd think.

Here's what I'm using…

BCW 4x6 Toploaders

Certainly not the cheapest option, but the hard PVC, aside from being the most protective and durable option, is perfect for damage tracking in DT (using dry erase markers), and I have my DT cards back to back with my DW cards in the sleeve. It protects them very well.

If you can get your community to order their sets together, it really cuts down on the cost.

I have a bunch of big toploaders as well that they sell at a card shop by my house. I never use them for dust though as the dust tactics cards are already dry erasable and I just mark "wounds" straight onto the dust tactics side of the card anyway when playing warfare (my warfare cards are glued to the other side of the tactics cards but I have most weapon stats memorized by now and can see by looking at the models how many of each weapon I have so I rarely ever look at the warfare side anymore) so I never put them into the toploaders. I have kept the toploaders for the custom Star Wars minis cards that I have made for custom units. Or for putting in 2 normal sized cards side by side. For example, I have the cards for C-3po and R2-D2 side by side turned sideways to both fit in the 4 by 6 toploader… Or Jabba and Bib Fortuna side by side…. or 2 different cards for Darth Maul (which I have 3 different stat cards that are all different) or Grievous who uses two toploaders as, including the card for him in his wheelbike, has 4 different cards.

But I digress.