Accordingly with the original post I would go for the GP Ultimate 40 size biplane, the reasons:
1. It fits the engine of your choice.
2. It is a biplane, as an option posted.
3. It is like a scale building and will fly very sport.
4. Building two wings surely will improve your skills, and as mentioned in the original post, time is not an issue.
5. Great Planes has great manuals which include pictures and tips to make your build easier and will serve for future buildings.
6. You may download the manual, before buying the product so you can get familiar with the process and buy the tools that you will need.
There are many other reasons to go with this bipe, but it is a pita to write from my cel phone, so I will post other reasons later.

Good luck on your choice and better luck on your build.
Alfred.