1. While most advice given here is good, there is definately some that is maybe well intentioned but not very helpful. Knowing the area you are based in I GUARANTEE that you do not need a larger machine to start up with. While some of the other concerns are valid the commercial model Honda you have will work. Some people do not understand the size of lawns you are targeting. When I started I was able to gross six figures with 21" mowers and three people. Calling a top of the line commercial 21" mower 'lowballer equipment' is ignorant.
2. Your lawns will not stripe for a long time, if ever. What height do you think you will be cutting at for the stripes you see on this site? Before you even try striping you need to know what you are cutting (type of grass) and its tendency to stripe or not. You are going to have trouble getting many customers that will be willing to let their grass get cut at the 2.5-3.5" that might even hint a stripe. The landscape market is very different here on the wet coast than most people are aware of. Your lawns will not need their first cut until probably March and they will have to be growing vigorously for the striper to be effective. You should be looking for winter clean ups, late leaf clean ups, and trying to find aerating jobs to line up for March. RENT an aerator, cover your costs and always leave a quotation for lawn maintenance.
3. I have to recommend that you at least work part time for an established company, even 1 or 2 days a week for this first year. You will get a regular paycheck and still leave 5 days a week for yourself. You can read the internet till you are blue in the face, but till you have walked a mile in someone elses shoes you have no idea.
4. Kwantlan College has some great horticulture coarses available, some cities also have some decent continuing education programs that will help (I know Burnaby does for sure). Even with some night school coarses I strongly recommend working part time for someone for a while.
5. What is said on any website needs to be analyzed, our mild climate and heavy rain falls really make our area different from most of the guys on this site. There are guys on here that think it is wrong to cut the lawn in the rain, while it may apply to their location, you would not be in business a month here if you did that. Every day I can learn something new about our industry from the web, I also read a ton more of poor/wrong advice as well.
6. Good luck, and check the help wanted ads.