Spacing two rows of MC's

Hi all,

I knew how to do this, but I forgotten and it’s driving me mad.
I am attaching movieClips in two rows four in each row, in a loop, but I carn’t work out how to get the second row and still space it on the _x. There are 8 MC to be attached so I’ve determined the end of the first row when it’s half the length of the loop, and then set the _x to 0 and the _y so it will be below the first row, but then I carn’t continue the _x on the second row.

I know this is easy

myXml = new XML();
myXml.ignoreWhite = true;
myXml.onLoad = function(success) {
if (success) {
} else {
trace(“XML not loaded”);
var btn_spacing = 95;
loadBtn = function () {
start = myXml.firstChild.childNodes;
for (var i = 0; i<start.length; i++) {
info = start*;
navBtn = nav_mc.holder_mc.attachMovie(“btn_mc”, “btn_mc”+i, i+1);
navBtn._x = btn_spacing*i;
if (i>=start.length/2) {
navBtn._x = 0;
navBtn._y = 29;
navBtn.name_txt.text = info.attributes.weight;