Airrabbit, getting a bit dramatic there...
Where I come from, square circuits are never done (I always have a chuckle when I see a FCTM with a square circuit diagram akin to a Cesspit POH), descents onto final from MDA are commenced when you hit the nominal 3° slope after turning at 40" (+/- ½" per knot) and you roll out at 500ft AGL, 1.5-odd nm from the threshold. Just like a normal circuit/traffic pattern. With Vis of 5000m (ie low level VMC) Simple.
As for config, we have the Landing checklist completed before the base turn point. Nothing to do apart from fly around the turn and land.
Call it a cheat sheet procedure if you like; it works in the SIM and in real life.
Edit: Sorry Cosmo, I didn't see your last post above Air Rabbit's. Rolling out at 300ft in a jet is dodgy; ironic, isn't it that on a gin-clear day the stabilised approach criteria is 500ft, when the weather is cr@p, it's only 300ft? BTW, 3.5° is 4 whites on the PAPI. "Go Around!"