Rod Gervais Hemholtz res corner trap Dimensions

Hi this is Brad. I am building a small 10' x 16' Control room in a house in New Jersey. Walls two layers 5/8 sheetrock, with Kinetics isolation clips. I have Rod's Book "Home Recording Studios, Build it Like the Pros " I am Build the Hemholtz Slot resonater CORNER Broad band Bass Trap.The book shows Ix6 with 1/2 inch slots. I don't wish to Detune this so Should I assume Standard American 1x6 which would be a true 3/4 by 5-1/2 or should I cut boards to 1x6. I assume the slot gap is what is most important. But I would think gap depth might have a big effect. One other question. I wanted to build Rod's super door. My contractor did not want to deal with the " health Risks ". There is also a baby in the House. I assumed We could seal the door tight so the lead would never be exposed. Any ideas on this? Thanks Brad