I like both my Zebra 301 and 701 Zebra pens and want to get a 301 compact, just I don’t think a lot of the supplied ink.

Therefore I want to change the refill. From a bit of research online the following it seems can be made to fit/actually fit:

Uniball UMR -87 – the refill for the signo gel pen
Zebra J gel rollerball refil for the Sarasa Gel pen
Zebra JK gel refill for the gel 301 – this should just fit?

Seen the fisher pen mod but its expensive to get hold of fisher refills in the uk
http://edcforums.com/threads/zebra-f-701-mod-fisher-refill.77993/

Any one tried this – especially the uniball refill as its archival ink?
cheers