Progress...
Once I was happy with how clean the inside of the #2 crossmember was I sprayed weld through primer.
I made a re-enforcement plate for inside the cross member. Plate is 1/8" and ya I primed the back side of it too.
Had a few areas that needed to be dealt with in the crossmember. One other hole besides the one pictured above and one area I felt was just to thin to leave in place. So all up the crossmember got three patches, made from 1/8".
Took welds down just to provide a smoother surface, my thinking is, less for dirt/debris to grab on to. Drain hole went from 5/8" to 3/4" in size.
But of course on the outside, it has got to look like I never patched it!
Cheers