Some great tips on assembling the vacu-form fins and fairings here:Starting work on the fins.
Man, I really, really, really considered making these out of balsa wood or plywood. Or purchasing some aftermarket fins.
But, to stay true to the project, I will use what I have.
View attachment 374775
View attachment 374776
https://modelrocketbuilding.blogspot.com/2011/05/estes-saturn-v-build-part-19-fins.html
Fins are covered in parts 19-21 and part 32. Scroll down the right side for the posts.