You can do a few different things with materies for him. 21/0/9 is pretty standard though you can go to 21/9/0 fairly easily if you find that you arent ability spaming. You can even try a 19/11/0 setup (losing a point of vampirism normally and usually grabbing 2 armor, 2 minion reduction, 4 Heath gain, Vet Scars and the 2 points of 1 point damage reduction) if you think that you are going to be SUPER aggressive early. I think there's a 23/0/7 Corki setup floating around somewhere that gives Corki both the Attack Speed -> 10% armor reduction AND the Cooldown -> 10% Magic Pen but I'm not familiar with the exact setup or how well it works.
As for a build I'd go standard ADC in most cases. Zerks, IE, PD, LW, GA, BT. I'm not exactly certain what you would be trading for the TF (BT? Sustain loss is pretty huge IMO and nothing else really seems to make sense to me) so I cant really comment on how effective it is. Cant say as I'd see rushing it over the best DPS item in the game though (IE).