Informative Tips ...
 

Double clutching, gear shifting isn't about how many synchros your gearbox has and doesn't affect how your gearbox runs, besides your cars are very new. And you should give it time for the gearbox to run in properly. Here are some useful hints on how to run-in a new gearbox properly.

Shifting at different points - Don't constantly shift at the same RPM although you're also running in your new engine. That allows the synchros and gearbox to have the chance to rev through the general rev range. You don't need to redline or shift high, just shifting at different RPMs is optimum to help the gearbox run in.

Temperature control - As the weather is cold right now, especially in Sydney. It takes time for the gearbox to heat up, you'd find that shifting at cold temperatures is notchy (not-smooth) but once it heats up, it gradually improves. Being that the gearbox is also new, that takes a longer process.

If all else fails to improve the shifting/gear changing feel, look at changing your transmission fluid later on - Ala 5000KMs at least, and go full synthetic. Brands like Motul and Redline make very good transmission fluid that will dramatically improve your shifting. But remember, you need time for the gearbox to run in and that's probably the most essential step/consideration right now.