What's the best shoulder style bag solution?

Ideas please! I will accept multiple purchase combos if it works well. (Buy this bag, these straps, and this attachment) I'd prefer to be able to purchase easily in Canada. I am looking for a shoulder style bag like these:

• Athletico Ace Disc Golf Bag
• Rogue Iron Disc Golf Sling Bag
• Discraft Disc Golf Shoulder Bag

I am looking for 10-15 disc capacity, disc organization dividers, top load for easy access to all discs, secure storage for large phone, keys, and wallet, large bottle holder, discs easily slide in and out comfortable shoulder strap and firm comfortable handle (I switch between hand carry and shoulder carry), and a way to attach my retriever and towel. I have the Max Distance CF20 Retriever and towel if that matters.