Tenchi? Which one?

Ok so i want to start watching the tenchi series from begining to end right? Well, it turns out that it is much more complicated than i orignally thought. I know it's tough but could someone pleese tell me where to start?

This is just my preference but you can start with Ryo-Ohki OVA 1 to 3

http://en.wikipedia.org/wiki/List_of_Tenchi_Muyo!_Ryo-Ohki_episodes

Ryo-Ohki OVA 1 has 7 episodes (the 7th is a special)
Ryo-Ohki OVA 2 has 7 episodes (the 7th is ep13a)
Ryo-Ohki OVA 3 has 7 episodes (the 7th is a special and is the last ep)

then you could go to Tenchi Muyo GXP where the protagonist is a friend of Tenchi, Seina Yamada. his story is after OVA 3 or somewhere near it

Thanks I tried to go on the Anime database but their chart just gave me a headache.