You needn't sink to the level of business English. Proper English, including correct spelling, will help assure your clients that you are careful with all the details of your business proposals. Conversely, sloppy English will convey to your clients a strong impression of sloppy thinking.
You weren't watching the Pres. speech??
You really don't mind being wrong, do you? All the lawyers I worked with used "alright", but I'm supposed to take some twit's word on the internet for proper usage and spelling? I don't think so.