Hi RubyTuesdays,
Wish I could offer practical advice, but I have not been in your situation and thinking about it can only imagine how hard it must be to make a decision.

I dont know much about day 5 embies vs day 3, but I think that my gut feeling would be to try them and then go to the donor option. But given the lenghts that you have prob been to organise a donor etc, then I can understand your desire to go straight to that and have your remaining embies as a back up. Tough call with no easy option.

I just hope that you end up making the decision that is right for you.

Good luck and wishing for you a BFP from whatever option you choose.
FG