What Style rear main seal to install?

[VTM37]

My motor came with the rear main split plastic seal installed but has bolt holes for the flange style seal. I am not sure if i should put back what was in it or switch to the flange style. Or can I us both? I am just trying to avoid leaks and don't know what one works best. Best gasket sell both styles.

Thanks

[Cal_Gary]

Sorry for the delay-mine has the split seal with the h-shaped end gaskets. I replaced it years ago and it is now leaking again-likely because I didn't use enough sealer on the end gaskets. I can't tell you which is better but I think I'd go with the style that is currently in use in the truck, unless it has already been replaced but is totally failing again.
Gary