when you say cut & buff does that mean you've already cleared the car? If so you can scuff the clear with a gray scotch bright pad (3M), mask you're stripes & spray the base then reclear all over again. Be sure to wax & grease remove after taping for the stripes & before spraying the next coats of clear.

If your talking about cutting & buffing the base, thats not going to do you any favors. Dont sand base - unless to remove runs like you have, sand those out with p500 & re-base, you can spot that in w/an air brush if you have one then its a much smaller task.

The advantage to clearing the base then striping is the 2 colors wont blend & if you have problems you can sand them out of the clear w/o sanding into the other color...hopefully.

Are you catalyzing the base (adding hardener to the base - 1 oz. per qt. of base & reducer total) ck. tech sheet of paint prior to doing so but should be OK.

I hope your wearing gloves & not touching the base w/bare fingers.