That's exactly how I do it - I start at one number and go up, just using svbk or b4bk. Actually, unless I find something I want to call
Coach about, I usually just post what I find in black and leave it up to others to find out the other colors if they are interested in the bag. It is way too hard to start guessing other colors because there are so many color codes. But once people call and get info, that narrows it down a bit. So I agree - just searching by black (with silver of brass hardware) is usually your best bet to uncovering something new.