Windex & Soap have worked for me in the past. With both MK & UC..

The problems pop up when the graphic / detail is large, and trying to lay flat on a compound curve. Unless you're shringking it, you're gonna get wrinkles.

The Windex method, or soapy water allows a film in between the covering (wing) and the graphic to be applied. The graphic essencially floats on this thin layer of liquid. You then squeeze out as much of the liquid as possible. Basically squeegee-ing it out with a credit card (those 'free ones' you get in the mail..) or somethign similar. This also removes any trapped air between the coverign layers. Paper towel helps mop up any excess liquid as it's squeezed out..

Let dry. This is important, like, 24hrs drying or more... You want to ensure that all the liquid has evaporated. The soap helps it stick a bit, so I assume, like what you used to do to get grips on your bicycle handlebars..

Once applied & dry, you then run your iron around the edge of the graphis, to activate the glue, and ensure it is really stuck down. Don't worry about the middle parts. With MK, you can 'paint' the edges with the trim solvent.. You can also paint the edges with thin CA or clear nail polish to really seal the edges..

One key thing here is cleanliness. Clean the area with Windex, then with dish soap ( a great degreaser!) then with Methyl Hydrate (alcohol) and clean your hands too!!

The other option is to visit your local 'custom sign shop' and either:
1) Get them to 'cut out' your graphic on vinyl. The stuff they use for stickers, signs, and the graphics / decals on cars
2) Ask them for their off-cuts. Their "throw aways". (Tell them you need it for your wife's grade 3 class art project... you shodu get a bag full of bits & peices.. scraps..)
3) buy a nice sized peice, and cut your own.

The nice thing about the vinyl, it that it sticks, and is flexible to go around curves & bumps & such..