Here me out on this. White residue from coolant is the silicate based coolant drying on the top of the bottle. If your bottle has an old cap, check the sealing surface of the bottle, there is a little raised bead on it, make sure it has no nicks or dings, or it creates a path for coolant to escape under pressure. Then check the cap itself. If it's the original,or more than 3 years or 50k on it, just replace it. The full level cold should be an inch user the minimum line, the trick here is mark it with a sharpie when it's cold. Park in the same place, check it on successive mornings after you use the truck just like you did today.
Now to address another issue. The EGTs are a killer. You should be seeing peak boost around 29-32psi. You want more boost. If the tune isn't making boost, you need a different tune. Basically, the more air you put in the lower your EGT will be at any given point. So if you have a stok tune that with a stock turbo only makes 25 psi because it's one of those later strategies ford concocted, get a tune that commands more boost with stock fuel. Because a Powermax has a larger turbine than stock, the exhaust back pressure tables need to be rewritten, especially on an inferred EBP strategy.
Another area to consider is the intake manifold may need to be cleaned. You may not be getting enough air to the rear cylinders, causing them to run very hot. This is where the intake manifolds really suck. Unfortunately, they are stupid expensive to upgrade and that doesn't solve your issue. But perhaps a good application or two of Seafoam might improve things.
Finally, take the truck, run it up a hill, stop at the top, and check the temp of the charge cooler inlet and outlet with a temp gun if you can. The discharge should be a bunch cooler than the inlet.
One other thing, on a 6.0L, your tune vendor can change the fan engagement points on these trucks. I always ran mine so that the low speed setting was 195 and high speed was 210. That's about 10-15° cooler than stock. Sounds silly but it makes a huge difference. I wish the 7.3 had the same ability, that's a great system.
The Current Truck (Oct-2013 to Present):
1999 (Early) F-350 Lariat, CCLB, SRW, Black/Tan
7.3L Powerstroke, 4R100, 4x4, 3.73, 37x13.50-18s, '05 Axle Swap, 6" Fabtech lift, GTP38 "D66" turbo upgrade, SCT 4-position chip with custom tuning by me, Straight Piped 4" down pipe through 5" dual stacks, N-Fab full length triple steps, Pro-Tech cab guard and tool box, louvered 5th wheel gate, Hella 500 Fog and Driving lamps, much more to come...
The one I'll miss, (Mar-2009 to Jan-2014):
2000 Excursion XLT 4x4
6.8L V-10, 4R100, 4.30, 285/75-18, 271whp / 388wtq
The one I won't, (Jul-2005 to Sep-2012):
2005 F-350 XLT, CCLB, SRW, 4x4 FX4
6.0L PSD, ZF-6S650, 3.73, 35x12.5-18, 4.5" Lift