A spine tick isn't necessarily a death knell, especially if it doesn't break color. The problem is with the CGC's consistency over the years, so it's really hard to tell.
In general, my screening approach over the years has improved a great deal due to trial and (expensive) error. To get good at grading, you really have to be willing to accept the learning curve. If you pay attention, you begin to learn the CGC's expectations.
The importance of great (not merely good) lighting cannot be overstated. You want to hit the book with as much light as possible. It also helps to use different wavelengths of light. Be sure to use warm and cool lights. Hold the book at various angles. Scan the spine first, then look at the surface before ending with the edges. If you see a few spine tics that don't break color, set them aside for pressing if you don't object to the practice. Don't underestimate the importance of the back cover. The CGC doesn't, and neither should you. Look at the surface of the book for dimples, finger bends, creases, and all the other stuff you don't want.
Don't ever use cotton gloves. I've had more than one book slide out of my hands while wearing cotton. Make sure to get powder-free latex or nitrile if you insist on gloves. Honestly, and it took me a while to realize this, the best way to grade is with your bare hands. The tactile information provided by your fingers cannot be underestimated. Just make sure to wash your hands thoroughly with Dawn de-greasing detergent and dry your hands thoroughly.
I would place my books on top of a lightbox and start hitting them with various kinds of light. Any color breakage at all would result in the book being tossed into the rejection pile. I would then sell those on eBay or here on the boards to recoup some of the cost.
GET A JELWER'S LOUPE! Magnification is almost as important as great lighting.
Pre-screening is a must! Will help you learn the curve while saving quite a bit of cash. Let's face it, what are you going to do with a bunch of modern slabs with 7.5-9.0 grades at the top? You can hardly give those away.
Read all the advice on grading that you can. The Overstreet Guide to Grading Comics is a must-have. The CGC's grading manual, written by Matt Nelson, should become your bible on the topic. It's the most thorough book on the topic that I've ever seen. AMAZING. Just keep in mind that Overstreet and the CGC don't always see eye to eye on everything.
Participate in the "guess the grade" contests held here on the board, but keep in mind that going by the scan alone is a quick way to lose money. You simply have to personally investigate the book to make a decision.
My biggest piece of advice to anyone looking to tackle a perfect run like this is: VIGILANCE! I kept my eye open EVERY DAY for years to make this happen.
1. I would use the registry as a checklist. Every day I would search eBay for missing books. Most people on eBay couldn't tell the difference in "fine" and "near mint" but I was able to hit a homer every now and then.
2. I hired a few "hit-men" to keep an eye out for me at conventions. They had many connections with dealers, and having many eyes out there looking helped me snag quite a few white whales. These guys would take the risk of sending off the raws. I just had to write a bigger check in return for their services.
3. I kept up to date with ALL national conventions and the appearances of any artist who worked on Spawn. I also had a small army of facilitators who would help me out.
4. I'd troll every brick and mortar I would come to. This only netted me a few books, however. Usually a complete waste of time.
5. I enrolled in one of the many "9.8 subscription services" to stay current with new releases and variants. I worked with two of these services. This was very expensive, but it practically guaranteed success. Spawn being Spawn, however, there were a few SURPRISE variants that slipped through everyone's fingers. Again, absolute vigilance, or should I say "obsessive vigilance" is the key to this, along with a lot of patience and very, very deep pockets.
I'd say a majority of my books were already slabbed when I bought them. Maybe about 30% of the entire run was self-submitted.
No way I could have done this on my own. The key is to assemble your own task force, as corny as that may sound. I always have half a dozen or so WELL-CONNECTED people helping me look....for a price, of course.
Also keep in mind that it may come down to the depth of your pockets, especially where auctions are concerned. I will be the first to admit that I overspent like crazy to make this happen.
Looking back, that was my general approach. If anyone wants more detail, please ask! I love discussions in this thread, so feel welcome to post with any comments or questions!