Weight is probably the biggest factor for me. I have found that the larger blades are easier for me to shave with as I tend to apply pressure against my face with the blade when I shave and having a heavier blade I apply less pressure. On the opposite end I don't feel the need to apply any pressure when stropping due to being able to feel the weight of the blade in my hand. I found small/light weight razors difficult to strop without pressing the blade against the strop.
The different grinds really aren't all that noticeable to me as far as one being better than the other except for the wedge 13/16 W&B I have. I must say that I do love the wedge but as long as I get a great shave I don't really have a grind preference.
I think shaving with any size razor despite its grind and weather it be a round or spike point is something that will take some getting used to and practice so there is no need to start with a smaller blade or a round point IMO. I tend to nick myself the first time I shave with any razor but I learn from it so I know not to do what I did again. I do recommend an affordable blade just in case you don't like straight razor shaving and the smaller blades are usually more affordable.
I hope this helps someone but keep in mind that I have only been straight razor shaving for about 10 months so I am no expert nor do I claim to be. :)