I own 3 coils, black/legacy/lf 9"and 11" and the white/hf 9" round.
Knowing what I know now, I would get a Deus with the 11" coil and save up to eventually get one of the hf coils (my optimal 2 coil setup). If XP sold the Deus with an hf coil, and I could only get one coil, I would get the 9" hf.
If you NEVER plan to upgrade your Deus with more than one coil, get the 9" lf/black (never say NEVER).
I consider the Deus to be basically 2 different machines if you have an lf and an hf coil.
For the lf coils, the only advantage of the 11" over the 9" is ground coverage but that has to be balanced against separation afforded by the 9". Depth delta between the two is minimal. I do not recommend the 11 x 13 lf coil, minimal coverage and depth gain vs. the 11" and way too heavy for the stock shaft such that the assembly feels unbalanced and the lower shafts flexes excessively. You really need to invest in a third party straight shaft setup which will cost additional $$$. Not worth it IMO.
Don't have the elliptical hf coil so cannot comment, but I am happy with the 9" round such that it has become my everyday coil. Geometrically, the hf elliptical coil should not have any additional side-to-side separation than the round since the center spine dimension thickness and length are approximately the same and that is what determines the width of the active search field on a DD coil. If anything, depth should suffer slightly due to the elliptical shape. The only advantage of the elliptical shape is it can be swung better in tight areas. The main advantage of the elliptical coil is that it can be operated at a higher frequency than the round, therefore, it's "electronic" separation and ability to resolve very small targets (it's primarily designed for small gold prospecting) excels over the 9" round (but the 9" coil is no slouch, either).
HTH
HH
