I'm sorry if this has already been said somewhere else.
But now that they nerfed the t12 2pc what glyphs to use`? Unleash lightning and flame shock then fire ele or lb glyph?
And when we got 4pc t13 what glyphs to use then?
This will likely change depending on your gear, but for me at least the best set up is Unleash, Flame Shock, and Fire Elemental. I tested this on simcraft with different fight lengths. The fight length obviously affected how much dps I gained, but I did gain dps at every point I tested. It might be worth mentioning that I have DTR, and am unaware if it affects the Fire ele's attacks, so it might be a higher dps gain for others.
Flame Shock's still one of the best for DPS, Unleashed Lightning is amazing for any fight with movement from both a DPS AND a quality of life perspective, so you're usually just considering the third. For that, you've got LB, LvB, and GoFET. LB and LvB are pretty dead even once you drop the T12 4-piece, LB tends to win out in sims but it's by less than 50 DPS. GoFET is, until you get your T13 4-piece, probably a really solid choice. The CD reduction works well with the reduced CD, meaning multiple summons per boss fight. Without the CD reduction from the set bonus, it's situational; it's maximum benefit is on a 7 minute fight; any less and you're not getting full use of the second summon, under 5 and it's just useless, any longer past 7 minutes and it loses benefit compared to the other two.
Generally, if you're working on progression, glyphing FET isn't a terrible idea. It guarantees it'll be up every fight, but you're basically taking a very slight DPS hit overall to ensure you don't take a significant DPS hit every 2nd attempt. If you're farming content, you probably don't want to glyph it once you're out of T12 set bonuses.