Depends what part of GT we're talking about.
For the Ultimate Dragon Balls Arc, Trunks confirms himself weaker than Goku, Gohan, Vegeta and Piccolo. As suggested by the Lood fight though, his SSJ self is still far above Base Galu, who I'd personally place in between Base and SSJ post-Rosat Gotenks. That said, I'd probably say Base Trunks ought to be around Pure Boo's level, with his SSJ self being far above that. Goten should be on about the same level.
On M2, Trunks is suggested to have gotten far stronger based on him being excited at the prospect of taking on someone far stronger than the previous opponents in GT and the combined power of his base self, Base Goku and Pan was able to instantly kill Base Rild with a Kamehameha, someone who didn't take fatal damage from Goku's Kamehameha in their 1 on 1 fight. I'd say his base form alone ought to be above a hypothetical post-Rosat SS2 Gotenks, with his SSJ self being probably stronger than Ultimate Gohan. After M2, Trunks ought to have surpassed Base Rild with his SSJ form from him resisting Baby's possession and Baby even pointing out how great his power was. Goten ought to be no different to his prior self until perhaps after Baby's possession. He was powerful enough after it that an attempted self-destruction was enough to overwhelm Base Gohan, who would be stronger than his Boo Arc Ultimate self, so SSJ Goten-Baby ought to be closer in power to Ultimate Gohan than Majin Vegeta was to Fat Boo when considering his self destruction was a botched one.
After the Baby Arc, they aren't suggested to get any power ups on par with before, though you could argue Goten did as the gap between them in equal forms doesn't appear to be as overly large as what the above feats implied. By the time of the Evil Dragons Arc, you could argue Goten caught up to Trunks considering Goten performed no worse against Yi Xing Long than Trunks did. Alternatively, you could argue Goten got boosted to being Trunks' equal by the end of the Baby Arc due to them bringing up fusion as an option despite how immensely Trunks would need to lower his Ki for that to work otherwise.