cerendir that sounds great! I'd say you're definitely on the the right track to capturing the 70s sound. It sounds just like classic Styx!
Although I haven't done any mixing with the intent of getting a 70s sound, I do a lot of keyboard / patch programming to get those kinds of sounds... one thing I usually do is to limit myself to only using plate reverbs, I think that was pretty much the standard way of getting reverb back then... I have no idea if this really makes sense but to me it keeps the reverb sounding "old"
P.S. For organs, you might want to check out GSi's VB3 plugin, it's only about $60 and it's a fantastic B3 simulator with awesome Leslie and overdrive.