the o5 does use the "D" tool for adjusting pilot screw. but not to replace the jets you want to install the jets then screw the pilot screw all the way in and then turn it out 2&1/2 turnes to start with.
the problem with re-jetting is that there are several stages that the carb picks up fuel from the bowl. At first or start up from idle or zero throttle threw about 1/4 throttle is all the pilot screw then at about 1/8 throttle the pilot jet kicks in and adds some fuel through out the range till full throttle but not much after the 1/4 throttle position.
From 1/8 throttle through about 1/2 throttle is affected mainly by needle diameter, then from about 1/4 throttle through about 3/4 throttle is affected mostly by needle shiming or clip position. About half throttle through about nearly full throttle is affected by the needle taper, and the main jet picks up from 3/4 throttle to full throttle.
I hope this helps you to understand carb set-up. a little better.
http://www.triumph-bonneville.com/images/TN4.pdf
