Turning Polish oil wealth into durable defense

If Poland exploited major Baltic oil reserves in the 1920s, how should it spend the money before 1940?

Buy large amounts of artillery early, then purchase aircraft later so the air force is not obsolete when war arrives.

Oil revenue gives Poland more defense money but does not remove the problem of technological obsolescence. Aircraft bought in the early 1930s would be badly dated by 1940. Artillery purchased in the same period would remain useful and could be organized around pre-sighted defenses on both German and Soviet approaches. Later spending could then acquire newer aircraft without sacrificing the long-lived firepower already in place.