Any delta-gun color CRT the same screen size form 1965 to the last ones made ~1980 should be compatible. Tubes made prior to 1968 will mark a 23" view-able area tube 25 (ie 25AP22) tubes made after '68 will mark them 23V (ie 23VAXP22). Look for delta gun color CRTs or TVs that contain them for sale.
Bob G has some 25EGP22 CRTs that might work
http://antiquetvguy.com/FramesetPage...FrameSet1.html
The ETF also has a large selection of CRTs that may work in your set.
http://www.earlytelevision.org/crts_for_sale_color.html
Or look for a early to late 70's solid state set with a deltagun CRT the same size like an RCA XL-100, Zenith CCII etc.