Agitation will be key.
Hahaha! "aggressive agitation is the all" 
The thing is drying times are going to start coming into play with the heat uhhm.. (absorption rates) and it's going to snowball into hitting the right windows in the proper time frames I'm no science guy so I have no proper terms here... Getting to first crack "on time" along with a proper drying phase and completing the roast is a balancing act and my gut tells me the TO alone isn't going to work for 1 kilo.
Even with preheat you have to watch out for tipping so you can only do so much that is going to get immediately sucked into the batch......
Of course we are all on guesses.
All we can do is place our bets and wait for the build and testing. 
I figure the worst that can happen is I waste a few hours and end up tossing most of it into the trash. Hey, it's not like that's never happened to me before.
I've roasted as much as two pounds in the UFO/CO roaster (12 minutes from a pre-heated start to 30 seconds into SC). The only problem with roasting that quantity is the motor is so weak that the stirring arms were reversing direction so often the beans weren't getting moved about enough. That lead to looking for a more powerful motor, and there it was staring at me from the BBQ we hardly ever use as a rotisserie.
If this thing works the way I'm envisioning it, the stirring arms (4 arms in an X pattern) will need vanes pushing the beans sideways. Once I get it assembled I'm sure it'll need lots of tweaking to get it working the way I want. My target goal is to have less than $100 in it and that everything I do is reproducible by a non-engineer.
