Rockrz, me tinks you are overthinking this project a bit
if you are locked into the slotted conchos you only need a small leather punch and a common box knife to create a common slit for running the attachment piece of thin leather thru the band
the thin piece can be had frum most local auto upholstery shops out of their scrap pile OR frum a piece of black leather furniture set out on the curb for free/trash pick up (marketplace and craigslist are great sources ... rare is the day when i don't see at least one )
for the slits you only use 1-slit/concho where the thin strip comes up thru the slit then over the center bar in the concho and back thru the same slit and around the inside of the band to the next slit
here is the same principle used for the pins on a watch band
as for making a slit simply punch a small hole just a bit greater than the thickness of 2 pieces of the thin leather at each end of where you want your slit and using a box or exacto knife cut a straignt slit between the centers of the 2 holes. POC
this method has been used for way over a century where a belt runs thru a knife or axe sheath so the sheath can be carried
the forces involved w/ knife and axe sheath carry far exceed those of your quest
slits can be seen here in belt axe sheath n camp knife sheath and special force's dagger
a BTW is in order here ... conchos come w/ several different attachment methods
a loop for sewing one on like a button and a screw for heavier duty
i like the screws best because they only require a small hole to be punched in the leather/fabric as in a hatband i quickly made up back in the 1980's
GOOD LUCK W/ YOUR QUEST
leon