B&6 A&5 does not make a crossover suitable for an M7, or anything other than an 0-4-0T, frankly.
At the ARPS Permanent Way seminar at Armley Mills in Leeds in 1990, Peter Olver, part of HM Railways Inspectorate at that time, recommended that a double line crossover be constructed with crossings of no lower number than 10 and absolutely no lower number than 8 for passenger lines in 12in scale.
A heritage railway in England constructed a crossover in 12in scale using crossings of 6 1/2 angle. I’ve travelled over it, and it came close to seeing the wrenching of corridor connections off the ends of Mk.1 coaches, even with buckeye couplers. This crossover had been replaced since, probably in response to the above recommendation.
Peco OO/HO large radius points have a crossing angle of about 1 in 5 1/2. It did not prove possible to achieve the propelling of Mk.1 coaches through a crossover built with them without buffer locking.