John Cutler
If you use A5 turnouts, you will not be able to reliably run large tender locos or bogie vehicles through them.
A5s were rare on the prototype for this reason.
I suspect A5 crossovers were rarer still.
By minimising the track centres, the reverse curve is accentuated in effect and will give more problems for larger vehicles.
In cramped yards, especially industrial sites, loose-heeled straight switches were more common.
These give a larger radius curve for the same 1:5 crossing angle and in a shorter footprint.
You could try modifying the A5 kit; the A switch blades can be used for the loose-heeled switches.
But you will probably have to incorporate some new sleepers and chairs and recurve and cut rails.
You do need to print a template from Templot.
I have a B6 to a 1:5 crossover in my yard.
By using loose-heeled straight switches for the 1:5 turnout instead of an A5, I can now reverse a short tender loco (Drummond 700) through it reliably.
My N mogul still complains though.
As regards couplings, my experience suggests AJs will give trouble on an A5 crossover even if all your buffers are lightly sprung.
Good Luck!