As you've seen if you've reviewed this year's tower posts, there are lots of ways to get to a competitive tower, and a range of opinions, both on basic approach and various details. What thsom is suggesting would work. What I suggested would work. They'll both come out in the 15, certainly less than 18gr range. What I suggested will be slightly heavier than what thsom is suggesting; it will also be more tolerant of a less than precise build.
Both should get you an order of magnitude farther along than what you have. Hardwood has no place; there is just no need. There is no need for anything bigger than 1/8th.
The wiki has some good info, also some less than good info; you probably don't have the experience base to tell the difference.
As I said at the outset, time is not your friend. You need to settle on an approach, and then build it as carefully as you can
Fort Collins, CO