when the "shark bites" came out, we were concerned about using them. To date we have used them many time under sinks to add trap primers and have had no failures in the past 3 years. If you're tapping the cold line under the sink in the kitchen, Im assuming that its 1/2" pipe coming out of the wall into the angle stop.. thats where i would put the shark bite tee. Just be careful when you slide the tee on that you push it straight so you don't knick the o ring inside the fitting. If you are worried about connecting the bib to the outside wall, There is an item called a "quick bib" which is used with CPVC which has the same outside diameter as CTS sized pipe. The only issue i can foresee if the slants of the vinyl. The bib is going to sit flush on the siding at whatever angle the siding is unless you cut a hole and mount the bib directly to the wall underneath. Thats if you are using a silcock. If you use a boiler drain instead, you can just stub the pipe out of the wall and put a female adapter on the end (1/2") and simply screw the valve into it.