Why not just re-create the nodes when you need them?

If there are theoretically 500 million nodes, but you are only using some of
them, then it sounds like you are creating nodes unnecessarily. Why not only
create things when you need them? Or indeed, revisit your algorithm totally and
eliminate the nodes entirely, or only generate some figures and interpolate, or
whatever.

Production of 500 million reference items is not a common thing to do -
especially as you don't then use them all. Much more to the point, it is not
normal to do it in a semi-interpreted environment such as Excel VBA.

Try to eliminate your problem  rather than trying to shoe-horn a solution into a
system that is not set up for it.