If using waxy maize then just go buy corn starch. All waxy maize means is well waxy corn. Pure gimmick...As with most supplements.

From what I've heard Waxy maize does a better job of allowing items like creatine to be absorbed vs dextrose may be better for pre workout. Id also take maltodextrin into consideration over dextrose PWO because dextrose usually leads to a insulin spillover (Fat gain for me at least) in meals after my PWO shake. Where as with maltodextrin I don't notice that as much, I'm going to guess this is because although not as fast absorption as dextrose (is it really necessary I believe the window is something like 2 hours for glycogen replenishment) It doesn't lead to as quick of a drop of insulin and blood sugar as insulin does.

I use Universal Nutrition's (same ppl that make Animal Pack) "Torrent" for a PWO drink. Its the stuff in my profile picture and it has waxy maize in it. I obviously cant feel a difference but its suppose to be good. Waxy maize is suppose to have a "snowball like effect" where it helps pull in other surrounding nutrients (amino acids,creatine,ect..) into muscles quickly. I recently bought a bag of pure waxy maize real cheap at 4.76lbs for $20. I mix it with a scoop of creatine daily. Here is the link from where I bought mine. It sounds like a decent product for the money.
http://www.bodybuilding.com/store/jsn/glycocharge.html