The main damage events from the fight come from 464839 and 458277. The boss will do the first 464839 53 seconds into the fight, the second one 28 seconds after that and then 458277 around 15 seconds after the 2nd 464839. One minute after 458277 the 464839s start again and repeat until the boss or your raid dies
The cycle is around 1 minute 40 seconds, which means you can perfectly line up your stasis to cover the most dangerous part of each cycle and Flameshaper plays amazingly into this.
If you fill your stasis with engulfs to heal the damage from the second 464839 1:19 you can release it at 1:35 to heal the raid from 458277 and it will come off cd at around 2:50, ready for you to set up your burst again for the 464839 at 3:02 and 458277 at 3:13
Conversely for Chronowarden, you can use your stasis to do a big lb ramp for every 458277 and simply do smaller ramps to cover the 464839s. This could be less healing overall but it might be even better for progress because you can manually echo the people getting marked for mechanics so they get extra healing and so are sure not to die on the most dangerous moment for them.
Regardless of what you end up choosing to do, the fight is not very complicated and the biggest pain points will be properly positioning during 464233 to drop the images and then making sure to destroy all of them with 464839