Well, its ultimately your car, so you can do it if you really want. Although I know my transmission very well, and can and generally drive it just as smooth as automatic now that I'm familiar with it does not mean that I don't on occasion mis-time a shift. Just the nature of being human.
Slightly off topic, how do you like the V6's transmission? I'm in love with the TR6060. Other than them making 4th and 5th ratios ridiculously close together.