Driving to Texas and Biodiesel Planning

In two days, I start driving for Texas in my Volkswagen Jetta TDI. I've been running Biodiesel (B99 - 99% biodiesel, 1% petroleum diesel blend) for the last three years, and I'd prefer to run on as much biodiesel as possible while I drive to Texas. I have a few constraints though - it won't be time efficient for me to pick up biodiesel on the way to Texas, so I'll only have what I carry with me (two 5-gallon fuel cans of biodiesel). Because of the angle of the opening to the fuel tank on my Jetta, I can't maneuver the fuel can to get more than about 4.5 gallons out. The last 1/2 gallon is stuck in the can. Also, for emissions reasons, I'd like to run as close to B20 (20% biodiesel) or higher as possible. The last constraint is that I can't get fuel again before I leave (the fueling coop that I belong to isn't providing fuel again until Thursday evening and I leave Thursday morning) and I have 2/3 of my tank full of B99 right now.

I could run B99 for as long as possible (about 850 miles) but then I'd be running pure petroleum diesel for the rest of the trip. Here's the plan that I've worked out:
- Fuel up in Santa Clara with petroleum diesel before driving to my parents' home in Los Angeles. After fueling, I'll be running approximately B66.
- After spending the night at my parents' home, fuel up in LA with petroleum diesel without adding additional biodiesel. B29
- Drive to Tucson, AZ where I add 1/2 a can of biodiesel (2.5 gallons) and then top off with petroleum diesel. B22
- Drive to Las Cruces, NM where I spend the night. Drive to El Paso, TX, where I pour the rest of that biodiesel fuel into the tank (about 2 gallons). Fill up with petroleum diesel. B20
- Drive to San Antonio where I pour in another 2.5 gallons of biodiesel and top off with petroleum diesel. B20
- Drive to Austin with 13-14 gallons of B20 left in the tank and 3 gallons of B99 in fuel cans.
This method should allow me to have some time to run on biodiesel while in Austin as I look for a new source of biodiesel.

(The alternative method that I first came up with involves:
- Santa Clara B66
- Los Angeles B29
- Tucson (use entire fuel can of biodiesel) B32
- El Paso (don't add biodiesel) B15
- San Antonio (use entire fuel can of biodiesel) B28
This leaves me with 13-14 gallons of B28 and about 1 gallon of biodiesel when I arrive in Austin. It's easier because I don't have to pour half a fuel can of biodiesel into the tank, but I think I still prefer the first method that I've written down above.)