Yogi's guide: you're walking 2600+ miles, I'd get it. Take the advice you like, ignore what you don't but it's worth reading, and I liked having the "town guide" stuff along with me.
"So from my experience I would suggest taking it easier through the sierras and probably going out at Kearsarge."
+1, though a lot of people are sold on the idea of "staying out" for as long as possible through the Sierras. My focus was to minimize food carried, not least because it was tough to force everything needed into a bear can. So I had a box sent to Independence; Kearsarge pass is a fairly long side route, but worth it for me. Then I went to MTR rather than VVR, a faster approach, minimally off-trail. This split the distance between Independence and Mammoth Lakes rather well.
+1 on a food drop to Stehekin.
To Greg, I wouldn't send boxes to Big Bear, Ashland, or Mojave --- those at least all have good sized stores.
Shoes: 500 miles per pair sounds about right for me; I think the Sierras were a bit tougher on shoes than other parts, but can still get 500 miles easily on most pairs. As someone else said, pointless to ask what model is "best", have to figure that out for yourself (see several threads on this topic here and on other backcountry forums ...).
If you do go with the "lots of boxes" approach, think through exactly why a given box is going to a given location, because there are definitely downsides. I.e., schedule adjustment to wait until post office is open, unwanted or excess food going into hiker box offsets cost savings (as does postage). I think that a person who already has significant long distance experience will be better able to make up a box that they'll actually want to receive later on but, ironically, that person is likely to have less boxes to begin with. After learning my lesson on the PCT, I was happy with 5 boxes on the AT (new shoes in each), and I'm thinking something like 7 boxes for the CDT.