Here is link to an image of the AC to AN adapter I cited:
Note that they don't recommend this for anything other than heater hose. The basis of this non-recommendation is probably due to the reluctance to using PTFE and CPE hose which is arguably incompatible with refrigerant (permeation). Perhaps they hadn't considered hard line compatibility where aluminum or stainless steel isn't incompatible. This is for AC #10 to AN -10 and AFAIK there are no versions of this for AC# 8 to AN -8 or AC#6 to AN -6.
However, I see no reason why someone with a small lathe and the skills to use it couldn't simply fabricate #8 and #6 versions of them from billet aluminum. IOW, there is a business opp'ty for someone here.