Lynn, too bad about your experience with the old balsa. It is often a challenge to work with old materials that don't behave as well as when they were new.
We've recently completed a much modified Phantom Flash that we modified for swing control. We built it for the 'Comet dimer cookup' at the Stick and Tissue forum. First we took a jpg copy of the PF plan and worked over in MS paint until a page sized plan of the basic shapes of the PF was obtained. Also the wing span was reduced to 14 inches.
Then these were simplified to develop an easy to build sturdy model for swing control flight. The win tips were squared off and larger wood sizes were used for construction. Wood used for the wing was 3/32 sheet.
Ribs were strips cut to fit the wing notches. Then the high point was located at 40% of the wing chord and the ends of the strips were shaved down to blend with the wing spars.
Tail surfaces and fuselage were made from 1/16 balsa.
Forming the wing dihedral and forward fuselage. The wing, horizontal tail and forward fuselage are removable for storage and ease of repair.
Al