Boards I have worked with have come from vendors who used an adhesive to
hold down the parts.  This prevents them from tombstoning. It is an extra
step but the results are worth it.  And there is no limitation on trace
shapes/sizes then.

One vendor did have a problem correctly applying the adhesive and on small
parts (0603 x 4 resistor nets), they would sometimes put too much glue down
and it would cover the pads. Very bad results. The problem was due to the
screen vendor using too large of a pattern for the small networks allowing
too much glue to be laid down.  Once that was corrected, things went ok.

On boards we assemble *by hand*, tombstoning is a real problem but my
feeling is transmission line effects over-rule it: design the correct board
(as you seemed to have) and then find the correct vendor to assemble it.
(Easier said than done)

Good luck!
Tom

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