Squashy looking tyres? That's a new one on me! All tyres with the same size profile will look the same, unless they're a particularly good brand like Michelin or Bridgestone that have rim protection on them. Even then, one wouldn't look more squashy than the other Also, 452s have soft sidewalls, which is why you need to up the pressure slightly when running them.
Crazy idea, but if you get on Camskill NOW, you could order a single tyre to be delivered there tomorrow, and just run on the spare until then. Surely that's the best idea, and saves you money too? Please don't make me break into a rant about mixed tyres again, I've been so good lately
T1Rs and 452s are dead tyres now, you're only prolonging the inevitable if you can find one in those sizes. VUS are gone too, so I'd go with the RE050A if you want a decent sidewalled tyre but without the cost of the MPSS.