Hi Weegee,
I too am just starting so welcome to the world. I'm flowing half-plate and 5x7 and find the larger size slightly easier, I can control the pour better. But, I've poured mostly half-plate to save on costs while I perfect my technique. ORM-D is a term used for shipping small quantities of hazardous materials. While some suppliers require some sort of paperwork the one I use, Art Craft Chemical does not. However, some of the chemicals sold are not shown on the online order form and you must call. No problem at all and you can have custom quantities shipped. Enjoy.