Sea to Summit Field Repair Buckle with Removal Pin(s)

Where are the measurements taken for sizing? Is it the overall width of the buckle or the strap you are attaching the buckle to?

Link is not allowing me to select 'color'. Link goes to 'size' when attempting to select color.

Will the non-adjustable part of this buckle accommodate a factory installed 7/32" thick tongue on the end of the 1" strap or do I need the 2-pin?

Will this work on a swinging chair and is there a weight limit