You sound a lot better prepared than some people here have been, posting similar plans. The weather window will be tricky, given the timeframe, but really, if you have three guys on a Westsail 32, you can "give her" 24 hours a day and still get decent sleeps on a six-on/six off schedule with two people awake at any given time.
I would advise the following: Make sure you can make a PRIVATE sleeping area with strong lee cloths. You are going to have the tricky nav parts at the beginning and the end of your runs...when you are most likely to be tired and anxious.
Have your rigging examined top and bottom for weakness. If the halyard are worn, change them. If they are still good, but have a few years on them, end for end them. Have the righ properly tuned/tensioned and tape cotter pins, etc. Put lanyards and clips on certain tools like needle-nosed pliers and get some of those West Marine rigging knives...at $9/each, you can lay in a store for dropping overboard purposes...
Have your sails examined and perhaps reinforced with triple stitching and chafe pads. Make sure your reef lines WORK when needed, and have preventers and jacklines riggable in a hurry. Rig anti-chafe of your choice on the shrouds. Bring a storm jib.
Have your fuel polished and bring more in lashed jerrycans. Heavy weather moves gunk (the best thing to do would be to have the tanks cleaned out, but you probably don't have time for that!), so bring spare filters, belts, etc. You could just as easily hit 400 miles of light air and want to motor a fair bit.
If you have a furler, service it and make sure the furling line isn't worn. You are intended to ride on a starboard beam or broad reach and this will be a fast run, but you may have to reduce sail often. Make sure nothing catches or squeaks. Bring spare pins, shackle, and Allen keys you can't drop overboard!
You have the wrong boat for a fast passage, but you have the right boat for a safe passage if you get caught out. Carry double provisions and water. This means if you have to detour big time to avoid bad weather, you can head east or south (Bermuda? It's an "out"...carry a chart for it) or just hove to for 48 hours battened down if needed. Make sure your radio's in good order so you can listen to weather and can tell the Coast Guard you are fine if you have to stay out. Filing a sail plan to this end is prudent.
Lastly, if you are personally concerned with going offshore, try to crew this summer on a short passage on a similarly sized boat. That should tell you if you are up to this. Your boat sounds close to being ready as it is.
Good luck...sounds like a blast!