Help with mattress

Hello.
Firstly I'd like to express my thanks for such and informative website, very useful and certainly has me interested in your products.
I think I've maxed out my research but have a couple of questions. About us. I'm 6'4, 15.5 stone, partner 5'6 8 stone. Both sleep on combo of back and side. Prefer a slightly firmer feel, but not too firm. We both like the visprung herald superb or regal superb.
1) what would you recommend in your range?
2) your site suggests the herald is 'similar' to the Artisan bespoke while the regal is 'similar' to the bespoke 004. This seems odd to me as the regal is superior in price and quality to the herald. I don't mean to make this about visprung but they are the ones we tested. Could you elaborate on bespoke vs 004 and specially on firmness
3) Are there advantages in using your base vs a 3rd party? 4) Can 3rd party headboards attach to your base?
5) what is your turn around time and how flexible on delivery time can we be? We are waiting on a house purchase to complete
6) if we purchase a 2nd bed from you, do you offer a discount?
Many thanks.