You asked about aluminum alloy, not carbon poles, so I will focus on those. Henry Shires has some discussion on his tarptent.com website about the superiority of alloy to carbon poles, so your choice may well be justified, despite the fact that I am a true believer in using carbon arrow shafts for dome poles. My choices are the Carbon Express Maxima shafts and the Easton "nano" shafts, but each to their own.
Tarptent uses the Easton .344" diameter poles, which are over 20% lighter than the thinner Easton .340" diameter poles. Quest Outfitters sells both for around $2.50-$3.00 per 18" section. If you can get Henry to sell you a pair of Scarp 1 13.5' cross poles for $30, you will pay only around $1.67 per 18" section. Plus you get the end tips, and cord (that is heavier than I use). Quest maintains the lighter .344" poles are as strong as the heavier .340", and as mentioned, Henry believes they are well stronger than carbon.
For purposes of comparison, arrow shaft weights are expressed in grains per inch (gpi). The .344" are 13.77 gpi, which works out to about 3/8 oz per running foot, not counting the ferrules, tips and cord. The DAC "feather light" .355" poles that come with the MSR Hubba are about 16.56 gpi. The .355" Easton Carbon FX poles that come with the MSR Carbon Reflex tent are 12 gpi. The carbon shafts I mentioned above run around 7-9 gpi, which is why I am a true believer in carbon. The trick is to design the tent so the carbon will not be bent to a tight radius in high winds, although I do plan to try some carbon poles with a Scarp and a Moment, which both have tight radii that will get much tighter in a high wind.
Quest also sells the .312" diameter Easton "Fly" alloy pole sections wich are 10.558 gpi. Easton says all of the above mentioned poles have the same "Ultimate tensile strength," but I would think the lighter ones with thinner walls would provide less resistance to shattering or other failure. They are all 7075-T9 alloy, so I don't see how you would be doing any better by experimenting with arrow shafts made of the same material.
So you have a number of choices, and can get what you want.
Good Luck! Sam Farrington, Chocorua NH