If Berra stands by her, on the other hand, we're essentially making a coup against House Goku, which will likely not be good for royal authority and might lead to resentment against all members of the conspiracy (as Berra seems to be rather well-liked, Kakara might end up being more popular with the Vegetans than the Gokun).
you're making it sound like Kakara (The Gold, The Mighty, The Spirit Saiyan, The People's Princess) is less well liked than Berra
.
Honestly, IF we made a coup i think we'd have at least 3/4 of all Saiyan behind us, and probably more.
The Vegetan love us. The Gokun love us. The church WORSHIPS us (and i think that's at least a full fifth of the population by itself).
Really, the only one who currently do not like us are those few Vegetan who believe that we were for the sealing (and it won't be for long) and Dandeer (and whoever she has under her control. Like those Saiyans who attacked the prison some time ago and that i am SURE were mind controlled by her)
And really, a passive Genkidama (+ those we can reach without risk of interception, mostly the Senzu) gives us pretty much a free kaioken worth of boost, for no cost, no strain, no risk of being sensed from the rest of the galaxy, and makes a powerfull impression
And really, i don't think Berra would ever try to kill us, even if WE went for the kill (which we aren't).
Even if he would, he would try EVERYTHING POSSIBLE before going that far.
tl dr:
1)If Berra is somehow mind controlled/manipulated against us, the power boost might make the difference in stopping him without hurting him too much.
2)If he is open to hear us out, it might still be usefull against Dandeer.
3)Better to have it and don't need it, that need it and don't have it.
4)It's much more likely that he'll ask us why we're using it that attacking us for it anyway. The only thing we're making clear by using the Spirit Saiyan is how important this is to us, which would be clear anyway when we told him.
On a completely different note, a couple things i really want to do after the unsealing:
1) I REALLY want to go visit Gohan Jii-chan. I was waiting for us to have the vision to spare, and we have it now.
We should also consider training our sight more, just for what he (and all the other z-fighterz) can offer us if we can visit them more often. For one, they can tell us what's the problem with the fusion dance (Goku showed it to the kids ONCE and it was enough!), how to cope with the "feeling everything die" issue, advices for how to deal with 17 and 18, and maybe tell us about the other lost techniques (The Mafuuba/evil cointainment wave could be really usefull, for example. It would have been a decent (though worse) alternative to the Genkidama against Dazarel, now that i think about it).
I also want to know why they can't simply contact us with telepathy.
2)we might want to train the Genkidama after we get perfect multiform (and by the way, tienshinhan might have some advice if we can contact him through sight...). Imagine being able to charge the enrgy for spirit saiyan while moving and fighting (probably legendary talent, but one can hope...)
3)..we do need to complete transcendence and style training...
4)of course we'll now have to socialize with Jaffur and Jaron, but that's a given
EDIT: little side note: i'm slowly catching up to Marked for Death... so many pages!