Not sure what the switch has to do with the structures issue, unless you're planning to put the structure over the switch itself....in which I don't see a fit in any case.
One of the first concerns I'd have is the relative length of the Lionel 042 switch and the Ross #6. You can check this with the template file info on the Ross website. In fact, if you print this template, you can use it to determine your track/structure situation before buying. Here's the link...
Ross 6 link
The spacing of your parallel (assumed) tracks off of the switch is somewhat up to you. The Ross #6 will undoubtedly require more table length to achieve the same track spacing as the Lionel 042 (027 style) switch.
FWIW, always...
KD