700-900 grafts enough? (photos)

To be quoted 1500 to 3200 graft seem, as you put it "insane". Maybe you would need that many grafts over several surgeries to match your original hair density.  You cannot fit 1500 graft physically in such a small area.  If you can imagine that each graft is the size of a rice grain.

Thats what they are, just estimates. Given your pattern loss, stable pattern, and your desires, I would think that somewhere in the 750 grafts/side would be enough. Frontal hairline grafts need to be single grafts, adding more definition, but less density, so more is needed if you want a natural, fuller result.5-7cm2 is 2-3in2, so the area will require some density to fill in to make it look natural.Best.

You can do a small case. In this situation, it is always easier to add or touch up the procedure a year or so later if needed and you are not invested as much up front.  Also, they may be estimating a large number due to getting lower survival rates.  Not all clinics get high graft survival rates so they have to aim higher.

It looks right, assuming that your hair is average thickness or better. Some doctors SELL hair transplants when patients don't need it. I wrote about this below and published this in journals. I think that you will identify with this and I hope other readers also read it because it is a WARNING for patients to do their homework. 

Since you are doing the frontal hair line most of the hairs should be one hair grafts donut will look natural. For 1500 grafts should be sufficient to fill in the hair line and temples.