HELP REQ: The little straw...in the butt end of the feed.

[catbert]

One good thing about all the variables at play is you have several paths to what you want.

• adjust the ebonite feed to the nib and source or engineer a non-corroding converter nipple — the most challenging path, as you know
• tweak the feed channel in the original plastic feed for greater flow (there are threads about this elsewhere)
• find the right ink

Maybe try the last one first? It's amazing how a pen can be transformed once you find the ink it likes. There's a lot of ink knowledge here (Chrissy for one) and samples will keep your costs down.

All the above assumes you're still enjoying the process on some level — that you like working a problem. This is supposed to be an enjoyable diversion, after all.

My handwriting is too abysmal to opine on flex writing and flex pens. If the goal is beautiful calligraphy, letterforms can be practised with a pencil without having to fight a temperamental pen and one's own lack of muscle memory at the same time.