Alternatives for Erse Super Q Laminated Iron Core Inductors for Martin King OB Speakers

I am hoping someone can help a newbie. I am building Martin King’s open baffle speakers and have everything ready to go but have been waiting for Parts Express to ship the ERSE Super Q 4.0mH (0.22Ω) and 9.0mH (0.346Ω) 16 AWG 500W Laminated Iron Core Inductors for momths. However, I gather from reading a post here and from watching Danny of GR Research that Erse may not stay in business. I have looked around for similar inductors and am baffled (No pun intended). Can anyone help with alternative suggestions so I can get these speakers built?
Thanks,
Tom