Hello everyone !
My 1st post . I see there is a lot of people with lot of knowledge about flooring .
I like to know how offen would you use the spacers for installation of 7inch wide walnut planks ...One of the rooms is almost 50 foot long ..the others are 20 foot ..

Calculate your shrink and swell of that 7" wide board of Walnut. Then test the moisture content. Varify the MC of your region, and calculate your gapping. With that wide plank, it may be every row, or it may be not needed if the floor is already a little high on MC.

Very good !
I would rather use some bostik's best glue and staples , but my customer might want the aqua bar underlayment and staples . Certainly I would make sure that the moisture readings are as they need to be , on the flooring as on the subflooring , but should we anyhow leave some gaps , every 15 foot ?
Thanks for your reply . This is high moisture region of U.S.

Most manufacturers do NOT recommend using a trowel on glue + a mechanical fastener such as a staple...issues in the future...you are on your own...just a thought.

Cheers
Steve