I wish it was as easy as looking at numbers and what worked well for others, but it isn't that simple. I say just go with your gut Lou! You know we all love you and want this for you just as badly as you do. So my advice is, what do you feel is best for you? I am sure you and DH must be leaning towards one or another? Listen to your heart, look for signs that point you in the right direction, whether it be religious or spiritual guidance or just plain old fashioned instinct. That urge we have to either keep going... in one direction or another... or even quit. No matter what the choice, we know inside of us what is meant to be. I know IUI doesn't sound like it will work compared to the percentage that IVF gives you, but what if it works? And if it doesn't, you have the money for a better cycle later. But then, what if you don't want to cancel this cycle and use what you get, even if it's one good one, it could be all you need. However, if it fails, do you have the funds for another cycle? BUT, what if that one or two healthy perfect embies gives you that miracle? In the end, it's all what works best for you.
I know, not the perfect.. Here you go! type answer, but it's what makes sense to me. Love you girl! I wish nothing but best wishes and a shit ton of baby dust!