here is a couple pics horn bows I made a year or two ago ,, joe
birch bark covered Scythian horn bow,, bark is set at a slight angle
Korean horn bow birch bark covered,, bark is laid full length ,with lenticels at 90 degrees from natural growth
the Scythian bow has two layers of single layer bark,first layer ls applied in the opposing direction
the Korean bow has one layer only two to three layers thick
both are glued on with sinew glue, after the glue is dry all voids if any will be filled with bark ,as the glue will suck the bark down into the voids ..
a couple of fresh glue sizings, then dip the bark in the glue apply bark ..after the glue has set and is fully dry, wipe off glue from bark with a wet/warm wash cloth..