Why dont you do 5 ASs, and if the workload does get too much than you can always drop one. And with geog, i find unless you really wanna do it...you wont put the work in needed, so if its not your top priority subject dont take it, and dont do it for the wrong reasons. Unis do like variety, and it maybe good to do it incase you change your mind of what you wanna do. But you can always take it later down the line, say if you decide you dont like one of you AS choices, you can drop that and perhaps take up geog. Ive also known people who have done and extra AS whilst doing their A2s, though this would probably be a strenuous work load. But where unis like variety - they also like good grades and evidence of extra-curricla activities .
And even if you dont get an interview - thats what your personal statement is for, so you can comment on how you dont do just work - however if you do take 6 AS you probably wont have time for anything else.