Anyway, all we know for fact is that;
1. Base Gotenks (pre RoSaT) is suggested to be high SSjin2 tier;
Piccolo: “Yo-you idiot! What are you saying?! You don’t know anything about Majin Boo’s fearsomeness!
No matter how incredible you may be, at that level there’s still absolutely no way you’d be able to win!”
Piccolo referring to Gotenks' power as 'incredible' and talking about 'that level' is clearly referring back to how SSjin2's weren't able scratch Fat Boo imo.
2. SSjin Gotenks (pre RoSaT) is suggested to be stronger than Fat Boo;
- Piccolo flat out stating Gotenks would definitely fight Boo one day after they failed in base.
- Piccolo doesn't express any doubt about Gotenks being strong enough to wipe Boo out(quite the opposite really). He just wanted to see his speed (which isn't directly related to power in many cases) and Gotenks proved that his speed was more than enough.
- Piccolo only doubts Gotenks' ability to beat Boo when he realized they only had 1 minute of fusion left (not power related at all).
- Gotenks defusing is shown to be a comical way for AT to continue the series (ie keep Boo alive) like when he also powered down/defused when he was about to finish off Evil(Super) Boo.
3. SSjin Gotenks (pre RoSaT) is suggested to be in SSjin3 Goku's power range;
http://s1195.photobucket.com/albums/aa3 ... ianime.png
http://s1195.photobucket.com/albums/aa3 ... sedki2.png
Goku states that Gotenks' Ki was once 'up' ie drew his attention in the context and the only ones previously sensed from the Kaioshin realm were SSjin3 Goku and Evil (Super) Boo.
Yeah, that's it really.
To answer your question, Pure Evil Boo should be able to one shot SSjin2 Goku etc yet be one shotted by SSjin Gotenks(pre) and SSjin3 Goku but where you place SSjin Gotenks in relation to SSjin3 Goku is up to you really. They should be rivaling each other at least (slightly weaker/slightly stronger).