Don't size the array and create a new method that do this for you.
Type t
Global a:Int[]
Method New()
a=a[..10] ' Slice array to 10 elements (Dim)
End Method
End Type
n:t=New t
n.a[0]=10
Print n.a[0] ' Result 10
Print SizeOf t.a ' Result 40 (4*10)
j:t=New t
Print j.a[0] ' Result 10