Dell Poweredge R720 PCiE cards

I have a Dell Poweredge R720 with 8x3.5 drives. I have opened support tickets in the pass so my service tag # is on file.

I want to install (2) single slot PCiE cards in my server and want to know which cards are supported and what the max size for the NVME sticks. I hear the R720 doesn't support Bifurcation, so It wont support the dual slot pcie cards. Is that correct? also what riser card and slot on the card can the pcie card be installed on?

thanks in advance