It's 147% now. Ed: I bunged up, I just now realise the Catarina mod only affects Support Gem Quality. This is bad. Sadly this mean 140% Quality can only be reached with a double implicit synth item with unveiled Gem Quality from Haku. Makes the Catarina mod pretty useless tbh, I will revise my crafting now, I have to think a bit about this. Sadge.

Yet another ed: Some Gems can still go up to 149% in total with everything perfect, it's just that the Active Skill Gem needs to also have the Support Gem Tag (Predator for example). Any other Active Skill can only ever go to 141%, and those 2 last percentage points are very, very difficult to get. When recombining it has to keep the % Gem Quality from Haku, the +1 Dex from Fossils and the Synth base item. Also needs a free Prefix and free Suffix to be able to force +1 All Gems.

The base is the most limiting factor, last league I managed to get my hands on a perfect implicit weapon, but that was very late in the league.

https://pastebin.com/0uQtvnqm

It's the recombinators, making the impossible possible. Namely combining the fossil-only +1 Dexterity Gems with the drop-only Catarina veiled mod (+2 Level of Support Gems and 8% Gem Quality). The latter does not exclude you from crafting the 8% Gem Quality alongside.

With a perfect synth base (+1 Socketed Support, +6% Gem Quality) and the new Awakened Enhance, you can get a total whooping 147% Gem Quality. Your Support Gems will also be pushed to level 25 or 26 and a Gem Quality of 45%.

An interesting example of this would be Anomalous Archmage, at 45% Gem Quality it actually says you 'lose' Lightning Damage equal to 15% of mana cost, while gaining 90% of mana cost as Cold Damage.

Most interesting though is probably Discharge, even without the perfect synth base you can get above the 140% Gem Quality mark, making the Divergent Discharge have a chance of 70% to deal damage without removing charges. With the 30% from the helmet you cannot lose charges with Discharge, ever.

You also get about 10-12 Gem Levels with Empower, even more if you go for Awakened Support Gems. And with the new +2 charge rings...

Such an weapon would also not be too hard to make, it's mainly hoping to not lose the +1 synth base while recombining with Catarina's mod.

Ed: quick 36 Charge build I threw together: https://pastebin.com/NVT0UNa2

Ed: I just realised a level 5 Awakened Enhance is way, way over 100 Ex rn. Lvl 1 Gems are 4.5 Ex each, with levelling it's probably still around 50 Ex minimum. Ashes of the Stars 40 Ex.