DogPacks: Old Question, New Tricks?

So, a Dogsey newbie here.

I've been researching the net and our forums here for information on packs, saddlebags, and backpacks for dogs, but most of the threads I've found here (save one) are older than 2010. With the newer years, I'm expecting that models of packs have likely changed, and wanted to prod at the topic myself.

I want to get a very small pack for Eevee, our rough collie. We need to get her out more for experience, like on walks, the park, etc., but after getting to know her, I believe she would benefit with a very light pack to concentrate on. Something besides me that she knows, and gives her a job/purpose. I only want one big enough to eventually carry poo sacks, maybe a backup leash/collar, ID, a transportable water/food bowl, maybe a tiny bit of kibble and/or treats, and water - I'm thinking about stopping at 12 ounces or so.

We're still building up her own physical prowess and taking it slow, because she isn't even a year yet and I don't want to damage her joints or muscle growth. We've actually only been to the park twice for no more than fifteen minutes at a time last summer, once she was trained up a bit and had her shots, wormer, etc. We'll start out with an empty bag of course, and slowly move up from there. We won't be mountain climbing or anything, but I always make sure we have plenty of water on me and in the vehicle- I like my "kids" happy and comfortable!

Sunny D makes little orange juice packs at about 6.5 ounces a bottle that I think would be perfect for water carrying in her pack. They're not very wide or tall, and just about fit in a large pocket, lol. Plus we get to recycle. If anyone's curious, I think adding a few ounces of water every few trips would be a good way (once she's used to the pack and the weight of poobags, then a light extra leash/collar, the stuff I mentioned before), to add the last of the weight just bit by bit.

Hubby and I are weight training/cardio fitness nuts, so it's kinda fun to think that our girl will not only be working on agility once she's older, but also strength training. xD


Anyway. I am looking hard at the Wolfpack brand bags, but those three seem rather large.. They do seem to be great packs, however, since I've yet to find anyone saying that their bags rubbed their dogs or sat anywhere but their shoulders, and fit properly. Money is not an issue, as we have plenty of time before we saddle her up anyway, and I'm interested in her being safe and comfortable beyond anything else. I was wondering if anyone had any testimonials on these bags or another good brand, or has a similar breed/sized/long haired dog with pack experience?

Thank you all!