I think that should be ok. My only concern is that your outer layer magnets are quite weak relative to the inner layer ones. According to the calculator on the KJ magnetics site the 4x1.5 should generate roughly 0.14 lbs of pull force per edge (0.56 lbs per slice turn). I like that on mine, but I think it is on the high side of what is optimal. Mine is set up with the 4x2 n38s, which according to that calculator would be 0.1 lbs per edge, or 0.40 lbs per outer layer turn. It is clearly lighter on the outer layer turns, but I think it's a good balance. Your 5x1 n48s for the outer layer would have a pull force of 0.07 lbs per corner, or 0.28 lbs per outer layer turn. I suspect that is too much of a discrepancy from the 0.56 lbs on the inner layer.
Also, I'm afraid I don't have any calipers handy, so my numbers are based on the estimation of 2mm of plastic between magnets. That's pretty close, but it might be just high.