My questions:
1. What is the best source to purchase Ipe? OK to buy over the internet and have it shipped or should I buy local? Is there a reliable name brand? I have seen Ironwood brand Ipe and RealIpe, any thoughts?
2. I was hoping to use the Deckmaster hidden fastening system that screws into the deck boards angled from below? Does anyone have any experience with this? Would prefer not to face screw the boards in place. Do I have to worry about increased cupping using this method?
3. How long should I let the wood acclimate outside before install?
4. Is it OK to use two 1x6 fascia trim boards butted together to cover the 10" treated rim joist? Can I butt them tight or do they need an expansion gap?
5. Any problem with creating multiple 10 footlong picture frames with 2 rows of 1x4 that frame the 1x6 deck boards? I am trying to eliminate end to end butt splices on long runs of decking. Also if I picture frame the sections I won't really need to attach a trim cap to the ends of the boards.
6. Can I get away with no surface sealing? Was just thinking of letting the boards weather naturally.
7. I need to wrap 6x6 deck posts with some type of material, Ipe 5/4 x 8 is pricey so wondered if there is something else that you would recommend that would complement the Ipe decking that I could wrap the posts with that isn't so expensive. I was even thinking of having white posts and white metal/glass see thru railings. Maybe a composite like white Azek or Timbertek to wrap the posts? Cedar? Other?

Any advice would be appreciated.

Do not even think of using these on any project, especially Ipe. Deckmaster is about the worst hidden fastener system on the market. The design is all wrong. (think placement of fasteners) the holes are where they are. Worry about cupping. You can't place 2 screws 3/4" in from the edge of the boards. Then, when you drive the fastener (from below) how is the board held tight to the joist? This is a major PIA. Standard top screwing has many advantages, no disadvantages when you're talking Ipe. If you MUST have the look of invisible fasteners, choose another system.

A couple of other little tips:
1. NEVER drill a pilot hole into the joist. No matter how you attach the decking, hidden fasteners or top screws, the joist should not ever be pilot drilled. Pressure treated lumber is very green (wet) and it shrinks significantly. Therefore, a drilled pilot hole becomes larger. As the seasonal wet and dry cycles occur, the decking pulls against the screws. Some will come loose from the pilot holes. The only chance a screw has of staying put, is to go directly into the undisturbed wood fiber. And longer screws are not better, The longer the screw, the more it sticks up when the joist dries out. 1.5" embedment is ideal.

2. Finish is not necessary on Ipe. It will go gray naturally, no matter what finish you put on. The only way to keep the wood it's original color is to finish it 3 times the first year, refinish it twice a year for the next 3 years, and then annually after that.

thanks for the tips and advice on Deckmaster. Is there a hidden fastener system that you can recommend?