For JEE Test Series, you can safely opt for the old renowned coaching Institutes. They provide good tests. I can not mention their names here, for obvious reasons.

Revision is effective only when you are also solving questions of that particular chapter.

Whenever you revise theory of any chapter, make sure you also solve some extra questions of that chapter on the same day. Because ultimately, you have to solve the questions in your exam.

You can rely on the class notes to revise theory from where you studied that chapter. When you revise, keep writing the standard formulas in rough notebook for practice and most importantly solve all the class questions on your own while revising. Because those questions are very carefully designed by a teacher to give concepts clarity. This is a must to revise the chapter.

Now, if you have less time to practice . And you understand that I can not solve more than let's say 25 questions then you make sure that those questions are from the whole chapter, not just from one topic.

For this, you can go for multiple of 3 or 5 or even 10 depending on the time and situation to get holistic understanding of the chapter.

For test Series:
(1) Attempt full test and sit for the full duration. 

(2) Analyse all the questions. Correct , incorrect, unattempetd. Find your mistakes, write them on a page. And try not to repeat them again.

Most students do not analyse their tests. Then they do not get any idea how to improve. So, get ahead of them by analysing.

The most important thing is :

You have to revise the complete syllabus. Whatever you do for the first chapter, you have to do the same for the last chapter. Make proper plan , according to time left. And do not change your plan by other's influences. Stick to your schedule.

My JEE montor used to say, It is important what you study now, but what matters most is : What you remember on the day of exam.

Best of Luck!