So to be very frank, I wonder why you have singled out WUSTL in particular for your ED II.
WUSTL does have a separate engineering school (McKelvey), but it still requires its engineering students to take courses in humanities and social sciences, and it generally has a very competitive student body in that sort of area.
For example, per its CDS, its 25th SAT ERW for enrolled students is 730, and only 3% scored under a 700 ERW (I would bet that was almost entirely hooked students of some sort). Something like 19% of WUSTL undergrads are in McKelvey, so necessarily the vast majority must have had a 700+ ERW (if they submitted, of course). There are similarly low percentages in an equivalent ACT reading or writing range.
And again according to their CDS, 67% had a 4.0. 24% had between a 3.75 and 3.99, and likely only a fraction of that 24% was a 3.8 or lower (again, I would bet that is mostly hooked applicants). I note you said you had all As in Math and Physics, which implies to me likely your not-as-good grades were in classes that would reinforce the impression your relatively low ERW might give.
Again, I think it pays to be blunt about this, so to me your numbers appear to be very low for WUSTL. I understand the 800 is very impressive in isolation, but it seems to me that WUSTL is maybe not the ideal target for someone who has that sort of focused rather than broader profile, not even in engineering.
That being said, I am not one to insist you need to ED II strategically. I just wonder how WUSTL in particular emerged for you.