IMHO, find the lowest alpha hop you can (<2%) and use it instead. Ones like strisselspalt, serebianka, celia are often at these low levels.
As for aged hops, any low-moderate AA hop that has been stored at room temp or above for a couple years would suffice. Aged noble hops would be ideal but are harder to come by here. Aged US noble-variant are good as well (willamette, santiam, mt hood, cascade, etc).
Then there's the option of baking hops at a low heat setting for a period of time to reduce the AA and artificially age them. Never done it and don't know the temp/time you'd use.