Jessica - Winsor & Newton Matt Black is an excellent ink for Calligraphy, especially with broad-edged pens. Their India ink is great for drawing but doesn't flow as freely as I like. The Speedball India ink also requires the nib to be wiped clean from time to time and isn't the best flowing ink in my opinion.
I have no experience with Dr. Martin's ink you mentioned.
Higgins Eternal is a good no-fuss black ink for practice with dip pens. It is well behaved with both pointed and broad pens and cleans up easily. It is not as dark or opaque as the W&N Matt Black ink though.
Interestingly, Noodlers Black, although a fountain pen ink, flows very well in pointed pens for me, it isn't that great with broad-edged pens though.
I hope this info. is of some use to you :-)
-Salman