What order?

I am outputting some images to 3foot x 4foot vinyl banners and wondered if anyone could recommend what they thought is the right process order for the images, meaning; Should i do sharpening in ps raw or wait until all my tweaks (wb / levels / curves etc..). -also I will be enlarging in Genuine Fractals as even my raw file on Canon 50d still not enough for 3'x4'@150dpi. I also am really unsure how much sharpening to apply as well- do I simply view at (actual pixels) to get an idea of the amount?

Any help is greatly appreciated as I am sending files off to print Monday for all our baseball players..... Thank you everyone

I will sometimes do very light sharpening at the time of RAW conversion and then any sharpening to be done is normally my last step before I send to the lab for printing. It is done on an individual image basis as there is no one setting that fits all. I always sharpen at 100% and then at full view to see how it looks. On something like this I would sharpening and then take a 100% crop portion out of it and print it locally to make sure that it does look ok from normal viewing distance.

Something that is 4'x3' is going to probably be viewing from at least 8 feet away so when you are looking at it in 100% view it will look soft. Don't let that scare you.

Thank you ssim for the advice, its really appreciated when someone takes the time to help.
Thanks again for the advice

I never print poster-size and so didn't jump in with any advice, and besides Sheldon's advice sounds good to me.

I'd emphacize the need to proof-print a small crop of the image. You may find that the Genuine Fractals does best, but perhaps not, so you could consider a couple approaches. Be sure to sharpen after an image resize for best control and effect.

Thank you tonylong that's great advice. I probably would have sharpened 1st so thanks for the save.
So much to learn. I am looking for lighting (AB's) maybe fixing to give to photography business a full try and if it weren't for people willing to share knowledge I would be dead in the water........