I want to use different pens for different things. I use thick markers for big shadows simply because they’re massive and chunky and cover loads of paper quickly. I like Sharpies for scaled-down shadows and thick continuous lines. This dip pen set from Speedball is specially designed for sketching. https://ink-drawing-for-beginners68901.bloggip.com/37431106/the-smart-trick-of-how-to-draw-with-ink-pens-that-no-one-is-discussing