Spector owner here…. I bought this case and the bass fits quite snugly. There is no pressure on the headstock whatsoever.
https://www.sweetwiter.com/c588--B_Guitar_Cases?highlight=SPETRTSACSE&mrkgadid=&mrkgcl=28&mrkgen=gpla&mrkgbflag=1&mrkgcat=drums&percussion&acctid=21700000001645388&dskeywordid=&lid=58700008501175174&dsproductgroupid=&product_id=SPETRTSACSE&prodctry=US&prodlang=en&channel=online&storeid=&device=m&network=x&matchtype=&adpos=largenumber&locationid=9007818&creative=&targetid=&campaignid=20426646913&awsearchcpc=&gad_source=1&gclid=Cj0KCQiA2KitBhCIARIsAPPMEhLOiLOK68-JzWCUc2vUp00BDjchD_xi15h-5OkCijO_YjDlOL-_v7EaAvQeEALw_wcB&gclsrc=aw.ds
Without measuring, I’d say that looks to be the size of EMG DC40‘s. Add a solderless EMG Preamp (BTC or BQS) and you’d be good to go. Definitely measure first.