As an aspiring freelancer, I may not have a wide array of specific experiences in logo set preparation or StickerMule designs. However, I believe that the skills I do possess -- Adobe Illustrator and Graphic Design in general -- lend themselves well to this project. Furthermore, my strong attention to detail has always been crucial to my work, especially when translating design files into different formats.
In terms of portfolio, while I don't have explicit examples of logo sets for Stickermule sticker sheets, I can confidently say that my proficiency in using various design software have enabled me to create high-quality logos for clients in the past. Should you choose me for this project, I promise to bring the same level of professionalism and creativity that your project deserves.
Lastly, while PNG format is not foreign to me, given this is the format currently used for your logo files, I embrace new tasks and quickly learn new skills. Thus, I'm certain that within a short period of time, I can adeptly handle the requirements of working with PNG format for your project.