Waterman inks are good for a vintage pen. The only Waterman I have currently is Serenity Blue.
I have two of my half dozen Esterbrook pens inked currently as follows:
Copper J (broken clip) Venus Fine nib @ present. Came with a 2556, but it fell apart. I will probably just replace it. - Diamine Merlot
Blue transitional J (round jewel) - 1555 Gregg nib. - Diamine Blue Black
Andersen Pens in Appleton, Wisconsin has a wide variety of Esterbrook nibs beginning at $5.00. Not sure what it would cost to ship it to Canada, but wouldn't think it would be to much given the size and weight of a nib. andersenpens.com
I have no experience with the Sheaffer line of pens, but would presuppose that given they were more expensive when new that the were considered a "better" pen. Although the Estie's are robust little pens.