I always use 5 minute 2 part epoxy and glue everything with it. I find that the epoxy glue holds up forever and is easily sanded and reworked if necessary. I hold my planks on using metal push pins and T pins. Also on my finish mahogany planking on the sides and decks I lay out the frame locations over the finish planking with tape as a straight edge and I then use a Biopsy needle and score the planking to simulate bung plugs , then when I stain the Mahogany the stain settles into the bung plug scoring and when wiped off the whole model looks like it was screwed and bung plugged once it is Varnished.
I hope this helps.
Bill Young
Gainesville Georgia