Mark,
I have 2 Z20, 1 Z30 and a Z40, the 30L is the same size as a Z40 and its a big reel. Unfortunately the Z20 and Ryoga is not available in Australia, But they are available from PLAT in Japan.
The Z20 is 440g and the Ryoga Bay Jigging 200 series is 345g.
Personally. I use the Z20 with Hi-Seas Grand Slam red 30lb Braid (Paulus tested at 49lb) for 90% of jigging and bottom fishing. They have been upgraded with Carbontex Drags and are smooth as.
The Z30 is the same reel but slighly wider in the spool.
I have had these reels for 8 years and never had a problem. The standard drag will last a few years but the Carbontex is well worth the upgrade.
Mark