i agree with your reasoning on the A8s hand. He really isnt gonna bluff much since he shud have some SD type hands. I guess since he thinks we are fos then its a good bluff card.
Oops on misread hand, yeah id fold here n turn.
AK is std imo.
On 20xbuyin I think it works fine until you hit 100nl after that you need more to play 200nl imo, thats my plan to move back up but i have done it before so its not really any big learning curve risk.