Which reminds me Nomad- have you actually loaded guns, or do you just write to manufacturers trying to find out how to do it?
No, I just watch you and laugh.
I don't pretend to know everything like what some others do. When I am not so sure of something, I reach out to the experts and ask them and try to go with what they suggest concerning the use of the equipment THEY designed and manufactured themselves.
If you don't agree with what others have to say, that is certainly your choice but you don't have to be condescending, just be happy it is only spearfishing.
But anyway, before I bow out I'm going to show you a photo of why I don't load to the last tab first. It scares the hell out of me to load a gun in my garage, but did it because pictures are supposed to be worth a thousand words. The band is loaded on the list fin. It would be possible but difficult to get a wishbone on the front fin. Now imagine there is a third fin in front of that second one. Do you think you could get a wishbone on it? Maybe you could, but I don't want to struggle while pulling a band as far as my strength allows. I cut my bands as short as I can and still load them. I'm not holding than at full stretch and messing around trying to get them onto fins. I'm making one smooth pull that barely gets to the fin. If it's easy I cut them shorter. And now Imagine that three are slots instead of fins. Do you think you could get a wishbone down into those slots?
I still don't get you, it is obvious to me that it will be difficult to load a second band on the second tab from the mechs side as it appears in the picture you present here. I'd think that loading onto the second tab first will be easier to load than loading the band on the first tab first, i.e., loading band 1 into tab B and then loading band 2 onto tab/notch C (the one closest to the mech.). BUT, you are free to do whatever you feel is appropriate to your situation and you are comfortable with. For the OP, he can try loading the bands in different combinations and figure out what works for him.
Happy and safe spearing!!