I’ve done several decks with Ipe. It’s become my go to deck material. Currently have a building under construction that has Ipe for siding. I’ve blind fastened with good luck, but for the trouble now use trim head stainless fasteners. Once the deck weathers, you can’t even see them. The trim head screws must be predrilled or they will snap off.
I know that there are experts out there that know more, but I don’t space my deck boards. When installed with a gap I find the shrinkage results in an excessive gap. With pressure treated lumber I’ll put the boards tight because I know that each board will loose 1/8” in width. With Ipe, it still shrinks, but not as much as PT so I’ll space Ipe using an 8d nail.