Yea the chidori fusion would probably not add that much but with PS bein amped by TCm id see it gettin a 5x boost or more..
Added two final scenarios for t saus.
PS would amp the mode, but I doubt that PS would amp the jutsu since the jutsu itself is used through the Gudo Dama.
Momoshiki would win since Sasuke main forms of offense are chakra, which can be absorbed by Momoshiki's absorption. Then he gets one shotted by his golem.
Adult Sasuke w/ Bijuu Susanoo would probably shit though.
1. Tenseigan Sasuke would have physical prowess on par with Teen RSM Naruto, but he'd be faster since RG Sasuke>Base Naruto in speed. Adult Sasuke already has physical prowess on par with a superior version of Naruto.
2. While the growth of Sasuke's abilities can't match the power boost of the Tenseigan, Sasuke has the Bijuu here. So his Susanoo would shit on Tenseigan Sasuke's.
So in small scale combat Adult Sasuke probably wins due to superior physical abilities, Ameno, and his Meteor Busting Chidori (which should be stronger now) Tenseigan Sasuke might have more outright power in his regular Ninjutsu, but Sasuke's superior speed should let him land a lethal hit once he uses Ameno.
Gudo Dama were broken by something that created an explosion nowhere near what Sasuke's Chidori did in The Last, so he doesn't tank it with the Gudo Dama, nor does he tank it with his body. Silver Wheel and Golden Wheel are both dodged via Ameno, and his other Gudo Dama/Tenseigan attack is simply blocked with a lower level of Susanoo.
So that leads us to Avatar vs. Avatar. Adult Sasuke's dumps on Tenseigan Sasuke's in regular attributes, but Tenseigan Sasuke has Golden Wheel, which can cut the Moon. Thus Sasuke won't tank it. (unless we were to take OBD calcs seriously and put Indra's Arrow at Moon Level :lol :lol)
However, Ameno should let him dodge it at the last moment. Then Indra's Arrow turns him to ash.