After a false start with a bait & switch by an Amazon Merchant (where they sent us a "compatible" Drum Kit instead of a genuine one), we ordered a true HP Drum Kit direct from Amazon.
It got here sooner than expected AND it solved the streaking problem we've been fighting for a year now.
The HP products are more expensive than "compatible" versions, but in this case, you get what you pay for. (When you take into account the free shipping, it wasn't that much more expensive than a compatible drum.)