Coastairbrush.com has a wide variety of tapes. This links to FBS PT43 MICRO Performance Tape, a very flexible 1/32" wide tape. I'm able to get the rolling gull grey - white seperation on 1:72 scale Cold war USN aircraft. Can't recommend this tape (and site) too highly.
Just a tip... check and see if the kitchen foil you're using has a bright, shiny side. I had been using a foil that was dull on both sides. With the new foil's shiny side against the adhesive, it sticks like, well, glue.
Best of Luck
Dave
BlueNosers352nd,
Try this link. It's the official Mr. Hobby catalog leaflet in PDF form. From what I can make out, the clears on page 1 are in 10mL bottles, and the ultras on page 7are 170mL sprays. The ultras are also advertised as UV resistant.
A lot more is available here. It's the official Mr. Hobby EN(lish) page.
Hope this helps.