I would stick with one size dog, and serve a sausage of some kind. Think quality. serve a good dog, fresh topping ( no mashed peas, thanks anyway) Quality, Quality, Quality, give them a reason to stop in the rain. London has a very diverse Food scene, have fun with the cart, be creative, think outside the box……….Billyb

Thanks for your input Billyb. The reason I am considering the different sizes is that most dogs here are very small compared to what appears to sell best over there. I don’t really understand the sizing yet, but would I be right in guessing that 4/1 is quite large (thick) and the 8/1 somewhat thinner? Most people here would only know one the size of Herta regular franks. 

I thought it would be a good idea to give them the option of what they are used to and also a “jumbo” which you’d be hard pushed to eat 2 of.

If you have a moment can you explain the disadvantages of 2 sizes? To complicate things more I am thinking of having a halal dog also.

The thing to bear in mind is that things are different over here and I want to introduce people to eating tasty US style Hot Dogs from a cart like they see in the movies. I need volume though, I also want to offer real great quality for those appreciate it. Maybe they’d start off with a small basic chilli dog (£1.50) and eventually become addicted to large Sabretts chilli dogs (£3.50)? 

My head is starting to spin!!!