I am going to build a guitar in a few months and i will be using alder with a maple top. I am using PRS SE pickups, which were very versatile on my Tremonti SE before i replaced them with US Tremontis. I built a 'heavily chambered' (could pretty much be called semi hollow) guitar last spring and its tone has something about it that i love, so i was going to make my guitar into a semi-hollow guitar. But less wood = less sustain and im making this guitar to use to play along with satriani/vai stuff as well as bluesy jazzy stuff so i want it to have some good sustain. Here are the specs

Alder Body
Maple Top
PRS Singlecut shape
22 fret bolt on rosewood/maple neck
PRS SE pickups possible with coil taps
1 Vol & 1 Tone
Wraparound tailpiece

If my ramble has confused you then here is basically what i want: A guitar with lots of sustain that has a semi hollow type sound to it. What would you experts suggest i do?
Canoe cut it.

My PRS Semi-Hollow gets me compliments all the time on tone and sustain.