A 1-9"tw 243AI would be hard to beat. That'll allow you to run the 105Amax and 105VLD if you ever want to stretch the rifle out. I would never hamstring myself right out of the gate with a 1-10" or slower twist, IMO.
I've ran a 243AI with the HS DBM bottom metal and it fed very well. I'm currently running (2) 243AI's set up in McMillans in ADL and they feed great. I prefer the simplicity of the ADL when it comes to hunting rifles. I've played with the mag's and they are not for me. I just like to keep things simple.
Just shot this 5-shot group the other day with my heavy 243AI at 705yds while laying in the snow. I'm a big fan of the 243AI and there is no way I'd do a 6mm/6mmAI in a S/A just due to mag constraints when it comes to the longer high bc bullets.