I think if you are not orphaning the '50 "Showboat" there's no party foul there in plucking the axle.

There are a hundred ways to build it, and it practically snaps together, or did.

I can't access my '49, but, IIRC, it is possible to cheat the metal axle to get a little more lift in front. I have a dim recollection (it was 40+ years ago) of using short bits of brass tube to locate under the control arm (?)

Much better shown than explained, had a hard time seeing the chassis on the drastic plastics instruction sheet site.

Good luck!