I would probably go with a whole blood and plan to donate again in 56 days. Really focus on water intake.

I'm 60 and the last thing I do before I go to sleep is down 500ml of water and the first thing I do when I get up is down another 500ml. Also I keep a big jug of water with me at work.

If something changes and your Doctor scripts a therapeutic phlebotomy in addition to your donations, make sure you monitor your iron via an iron panel including ferritin. It seems us older guys can tank our ferritin easily and it's a royal pain to bring it back within the normal range while maintaining your H&H at normal values.