How tall are you? Just thinking first off you might want a 32 length to get more stacking- that is key with Thanaz. Secondly, they should be sagged at least a little, not hiked up- IF you cannot do this, then go up a waist size to 30. They will stretch out about a half size or so, but unless you really go crazy on trying to stretch them, don't expect to get a full size out of the stretch. If you look at the Zac fugly pics, you'll notice that the center pic, which is most likely the oldest of those three, shows the best fit on him; then the other 2 show after he's worn them for awhile and they are noticably baggier- this is the level of stretch you can expect. If you want the center pic fit, then you might want to consider staying with your current tighter pair, cause when they stretch they'll end up more like that center pic. If you want them very baggy (not flattering IMO), then go with a bigger size and when they stretch out and don't look good on you anymore, you can sell them in the mall to one of us relatively fatter people who can fit into them better.
Have you worn the thanaz cut before? My advice in general is that everyone has their own personal sense of style and if you know already how you like a certain cut's fit in a specific size, stick with what you're comfortable with. Don't let me, Z, army guy, or even Zac change your personal style, because then you won't be any better than Zac Fakron