Hey Sparx, long long time!
I'd not recommend mapping both your primary & secondary fire butting to your trigger unless it's 2 stage. Some of the planes that aren't equipped with both MGs & cannons have the DT/Bombs/Rockets etc., auto selected on the secondary. That means if you fire you're guns you'll also be releasing your secondary weapons if you map it like that. Best to keep your JS secondary mapped seperately.