Io farei cosi, intanto dichiara tutto e poi metti questo codice in Sub Activity_Create(FirstTime As Boolean).
B4X:
WebView1.SetLayout(0%x,20%y,100%x,60%y)
Button2.SetLayout(0%x,0%y,25%x,20%y)
Button4.SetLayout(25%x,0%y,50%x,20%y)
Button3.SetLayout(75%x,0%y,25%x,20%y)
Button1.SetLayout(0%x,80%y,25%x,20%y)
Button5.SetLayout(25%x,80%y,50%x,20%y)
Button6.SetLayout(75%x,80%y,25%x,20%y)