Ideally, I think Golden Cuckoo are e+ based? I don't know what yours are based on.
This is definitely something that GCM breeders need to figure out. Golden Cuckoo will never get accepted as a standard color if there is no standard. I believe many breeders on this page are working on ER based bird (ie: BCM based cuckoos). However, I know a lot of GCMs are also e+ based, and that is also the locus you'll see on Bev's Maran website. I think the popularity of the ER (mostly due to ease of access) will likely win over the e+, but the e+ has some nice color features to contend with. I personally have e+ hens, and ER cockerels, so I could go either way...
Basically, the sooner GCM breeders come to a consensus and move forward all together, the sooner it becomes possible to get it accepted.