Hello Meganskye, if you want to offer your arm size as well, please write it in remark box (in order form), and our tailor will adjust it for you. n_n
*Remark message like 'My arm size is: xxcm.'
*Custom size costume doesn't charge extra cost, but the processing time will be longer than standard size costumes; for this costume in custom size, we need about extra 1-2 weeks to make it (excluding the shipping time).