Love it when you find a team that you can come back to like that!
Tips for Bilbao:
1. Read the annual Bilbao guide on this site.
2. Don't give up on average youngsters and consider buy backs, you never know when you're going to need a 2-star rated right back for backup or even first team duties.
3. Sign all youngsters with over 3* potential by your scouts.
4. Sometimes you need to part with a really great player to bring through a youth player and invest elsewhere.
5. Plot your transfers a season or two in advance at least.
6. Previous versions of the game have had a bug where B team players ask for too much money, so be careful just accepting all demands.
Honestly, it's a very unique and enjoyable save so I'm sure you'll love it.