How do I connect a pair of switches in a Stack with a pair connected by VLT?

I have a pair of Dell 7048s in a stack, with SFP+ expansion cards in each. Then a pair of 4048s, connected by a VLT. I would usually stack and just port channel between the stacks. But the nature of the tech on the 4048s (Storage Spaces Direct) it is not recommended. So Dell advised the VLT, I have set it up but the switch ports haven’t 'combined' or anything to let me create a port channel. Do I just connect 1 of the 7048s (SFP+ card) to a port on one of the 4048s, and then the same on the other 2? I am worried about getting myself a loop. Any advice on connecting these?