Actually, not to be picky, but borax is not sodium bi-carbonate, that's baking soda. Borax is sodium borate (not that I knew that off hand
I'd say try it, nothing to lose really. They're both fairly common laundry additives so it's not a crazy idea... I don't know that they both work the same way (I have a feeling washing soda would be more effective) but it's worth a try.
As for the Simple Green, it's controversial because it's advertised as being environmentally friendly but it contains 2-butoxyethanol which is a toxic ingredient. I keep meaning to try the same recipe with another 'all-purpose' type cleaner instead but never think of it...