I'm going to try with GBL but have been trying to get some input from people on here to no avail so far. The thing about 1,4 BDO, though, is that your liver will process it with alcohol sequentially instead of simultaneously, so first the alcohol will be metabolized, and then only after that's done it'll metabolize the BDO. They don't potentiate each other. The other GHB analogues are afaik processed differently, I think the sequential metabolization is only a BDO thing. It's still not considered "safe" to mix them if you're doing it recreationally but I think the risk is more of coma and less of death with those two alone.