I am relatively green, but can offer some advice, and others can correct me if needed...
1.) You are going to want to dry hop. IIPAs are known not only for high ABV and high bitterness but also an abundance of hop aroma and flavor. Dry Hopping will get you this. I would say at least 2 oz. for a week in the secondary. Use any nice aromatic ho you like.
I would suggest listening to Jamil's podcast on Imperial IPAs : http://www.thebrewingnetwork.com/jamil.php
. you can download the mp3 there, it was on 9/11/2006. He will give a recipe and recommend hops and describe what the style is like, what the point of it is, how it works, etc.
I would not worry about aeration, that should not produce as much an acetaldehyde flavor as much as it would a cardboard flavor. That is more likely due to your fermentation and fermentation temp. Too high of a temperature can create these flavors. Acetaldehyde is a chemical created by the yeast in the process of converting sugars to alcohol, but if the yeast is healthy it cleans up after itself as well and this should go away. So if it was too hot and excess was created, or too much of the yeast died too quickly, these can lead to the off flavor. I am positive
Jamil mentions this in his podcast (I have not listened to his IIPA one yet) but pitch your yeast low, maybe 63 or 64 degrees or so, and for the first few days of fermentation I would stay at like 66 or 67, and then after most of the activity has died down you can let her get to about 70 and make sure you get everything fermented out nicely. A blow-off tube would not hurt for any high gravity brew, even when fermenting at a low temp. Sometimes the 1 gallon of headspace is just not quite enough. They are certainly easy enough to rig up, and after the first few days it should not be a problem.
Really let it sit in the primary for a while, probably 10 days, and check your FG to make sure it is really done fermenting. Then transfer to secondary and dry hop for a week or so. Then bottle and relatively soon there after, enjoy, vigorously. Hop flavor and aroma do fade with time, so something like this, so dependent on hop flavor, cannot hang out in the basement for too long.
Hope this was helpful!