Hi new to this forum. I am building a new home in northern Wisconsin on a lake where the soil is mainly sand. I had planned on installing 3/4 solid Hickory flooring wide plank whoever I also installed a hydronic radiant heating system. This system will not be completed for several years. I have since learned that the widest I could go with solid wood flooring with this system would be 3". I do not like Hickory in the narrow sizes. So I am now look at installing 7 1/2 engineered hickory hand scraped flooring Hurst Flooring. My question is will this engineered floor hold up to the sandy environment? Will this floor width be ok with radiant heat? And lastly will 1 1/4 staples work to allow me to safely staple down flooring to 3/4 sub-floor?

Hand scraped surfaces are protected from wear by the finish. The finish will wear fast if the floor is not kept clean and has sand on it. With a hand scraped finish you will not plan to sand it, only re-coat it after it shows wear. Modern finishes should not be waxed or covered with floor "shine". This will prevent a coat of finish from adhering. Purchase the color that you like cause if it is sanded you may sand through the top layer if you do want to change color.
Engineered can work with radiant heat. Follow the manufacturers suggestions.
I would use inch and a half staples if they don't penetrate all the way through the sub-floor.