I used the masking tape that came with the Tamiya Busa kit. It was finer grain and thinner than the Scotch stuff.
I have just done the RD500LC fairings using normal masking tape - the older Tamiya kits don't have dedicated masking tape in the kits - and it actually came out as good as, or possibly slightly better than the Busa
I think the results are due to STR's tip. Cheers mate!
There is a dark blue stripe which will go between the two colours so I can cheat by ensuring the stripe covers the bleed where possible, although this isn't quitre as per the original bike (see the pic below).
The primer bits will be gloss red, RC already knew that though I'm sure!
I need to go to a model shop later to pick up some clear orange and red (the Busa came with pre-coloured turn/rear lights) so I will get some modelling masktape then...