Can I increase decrease the golden kiwi size a bit?

You definitely can. We hand resize these silver or gold Bilbo and Gollum rings, and we can adjust it to 1/4 finely or other fractional sizes. Typically you can order the nearest whole size and then in the special instructions box on the cart page, you can write for example "please adjust to size 6 1/4 or 6 1/3", and we can handle it.