I'd give serous consideration to a race-track like architecture with
long straightaways for assembly and the launch/landing pads at the
short straights between the curves on the oval. Like so:

Service Bay Service Bay Service Bay
.-------Z------------Y--------------X--------.
| |
Pad-A Pad-B
| |
.-------X'-----------Y'-------------Z'-------.

Direction of Travel: ---

I would also stack Starship in reverse order. So Service Bay X and X'
assembly the nose. That is then raised and the upper and lower rings and
tanks assembled below at Y and Y' and finally the Raptors are installed
at Z and Z'. This simplifies launch platform and bay design because
everything works on one-level. Whether the bays themselves have doorways
remains to be seen. It would have advantages.

Everything is moved around the track on rails using diesel-electric
locomotives. Not shown are the sidings used to house the locomotives,
etc. when not is use. When merely cycling Raptors you might then need to
have vertical stations in bays X/X' and Y/Y' since you are not doing any
assembly. But then no heavy lifting required either. Interestingly
enough Z/Z' don't need vertical access.

You can play around with this to your heart's content...

Dave