A word of advice from someone that has modified MANY Pelican/ Hard Cases over the years for military, gov't, contractor, and personal use. If you have some quality HOT MELT/ Glue Sticks. They work wonders with adhering the different components to the boxes and with sealing up the connections as you make holes in the cases. Similar to other adhesives, Clean and use an abrasive to score the area.
I also use the Hot Melt to Re Seal after the connections are removed if the box is being re purposed. To each their own. This is just what has worked for us over the years.
Just had weird experiences with the various adhesives not holding up over the years. With the heating and cooling, then moving of them around, tosses and abused. Had many components 'fall' off inside the boxes. With the Hot Melt, it moves and wears just as the cases do, Since we use a similar plastic/ glue stick/ hot adhesive.
http://www.hotmelt.com/