St. Paddy's Day Stout Suggestions

I'm looking to do a dry-stout / Guiness style beer for St. Patrick's day. The suggested recepies I've seen for dry stout / Guiness clone are quite simple. No crystal, roasted barley malt and flaked barley adjunct. I've got a couple questions and a general request for suggestions.

1. Marris Otter or two row? I've never brewed with MO, although I probably should have for an ESB I made. What is the principal difference?
2. Does carbonating with Nitrogen beer gas really make a huge difference? I'm likely only going to make this one stout this year, so I'm not quite sure I want to invest in a new tank and regulator for a somewhat infrequent brew.
3. Please provide your guiness clone suggestions. I'll probably add some carafa II or III for the black-as-night aspect of it all.

1. Go with Marris Otter. If you're trying to do a Guinness style, keep it all European if possible. MO is a little nuttier, maybe a bit richer or 'more interesting' flavor than plain two row.
2. Not really. With enough flaked barley, you will have a fantastic creamy head without nitrogen. If you have access to a stout faucet, just it + CO2 will make an awesome pour.
3. Without hesitation, BierMuncher's Ode to Arthur is a spot on Guinness/dry stout clone. 2% acid malt gives you just the right bite. I'm fermenting 10 gallons now for St. Patrick's Day. It is fantastic. My last batch was preferred to Guinness on tap locally.

Cool, do you have a link to the Ode to Arthur I can crib from?