The heritage jersey is really balmains heritage not wests tigers heritage and therefore cant be used for the wests tigers.
The Magpies heritage jersey is equally as good as the Balmain one and both are miles better than the crap the merger has sold as a jersey.
They could alternate between one and the other. Have one as the home and the other as the away for the 3 years or however long you have to keep the same jersey, then switch them.
And then they could have the current Wests main jersey as their alternate.
Either that or use the only jersey I've ever seen with their combined colours that actually looks good. Gold and White double V on black. That's a classic that embraces both sides of the merger and doesn't look like someone vomited black,white and gold onto a shirt.