Wheel, tire,offset?

Hello. I am currently switching to 15 inch all around on my fish. I want to lower it just a tiny bit so that the tires fit inside the wheel wells but want as much meat under there as possible. So admittedly I have not searched this whole thread, sooo long. Any suggestions on tire size, offset, etc I am wondering if there is still a good selection at 15, or would it make more sense to go to something bigger? Although I am not a fan of skinny rubber, if the options are limited at 15 inch I may have to? Give me some tire sizes, offset ideas, just want to fill up those big wheel wells.
Thanks
Sparky