Nope, for you to use the Rinnegan requires the ability to use it. You can't use it's abilities without actually using them. So yes, Sasuke tells you by sayi g Kakshi or anybody(Sakura) being able to use it is that they can handle it.
To get as better grasp of this we should go back to when Madara and Zetsu talked about why Nagato was given his Rinnegan. Nagato was chosen not because he was the only one who could use the Rinnegan, but because he was the only one who could control the Gedo Statue aside from Madara himself. At this point the Uzumaki and Senju were mostly extinct and Madara needed someone he could manipulate and someone who could control the Gedo. This list became rather shallow, those being;
- Tsunade Senju
- Kushina Uzumaki
- Nagato Uzumaki
- Nagato's Parent(s)
Out of these, only Nagato was young and would be easy to manipulate. Tsunade being too old, Kushina being too old and Nagato's parents also likely being too old as at least one of them had to be related to the Uzumaki or Senju. Hence the choice to give it to Nagato was because of his age. The reason he needed a Senju was to control the Gedo. If this wasn't a requirement then he could've given it to any random Uchiha. Obito wasn't a planned addition.
Anyhow. This directly implies that
anyone can use the Rinnegan, but not control the Gedo Statue unless the have Senju power. Through Obito we are given more information, specifically the quote that reads;
Even this one eye's chakra and ocular powers are so strong I started losing myself. Yet I, who am not its original owner, was able to accomplish this much with just one.
This is Obito directly stating that at some point after taking in this power he could sense that he was
starting to lose himself to the power. This further implies a
progress and that the person can continue to start losing themselves unless they are careful with the use of it. This also fails to explain a few things however:
- In what sense are one losing themselves?
- Why didn't Nagato lose himself?
We don't know either answer, but we could theorized that Nagato lost himself in the power when he became Pain and went berserk with the Gedo. We can also theorize that "losing oneself" refers to being consumed by the power and being unable to fully control it like how Nagato was unable to fully control the Gedo and Obito was unable to fully control the powers of the Rinnegan.
All in all, there is nothing to back-up that Sasuke's Rinnegan was weaker than Madara's. In-fact we know that anyone would be able to handle Madara's Rinnegan, but not the Gedo based on the information we are given by Madara.
He never said anything about period of time, he said he was almost overcome by it's power.
I already covered this, but I'll comment on it directly for convenience. Obito stated that he was
starting to lose himself, not that he had almost lost himself and overcame it.
This is true and false at the same time.
Exactly how can this be false? We know that the Perfect Susano'o is tied to Mangekyou Sharingan and/or Eternal Mangekyou Sharingan. We also know that those who awaken the Mangekyou can use the Susano'o. We see this through Madara and Kakashi who both obtain the Perfect variant either before or without gaining the Rinnegan. Madara was also further able to use a base Susano'o without his eyes.
Combine that with what we know about the Sharingan and how its mostly just a physical storage of power that manifests when special chakra is released from the brain then it would be pretty safe to assume that once you've awakened the Susano'o and Mangekyou Sharingan itself, you can use the Susano'o regardless of what eyes you have, only that for each eye you lack you also lack power as you lack part of the "storage".