I have to recommend against the approach you're taking for a few reasons:
1) It's very hard to find quality verbal questions outside of official materials. If you are on a budget and want a ton of verbal questions, they aren't going to be of high quality (unless they are illegal copies of official problems). The GMAT spends about $1,000 to develop one question! So in short, the resource you're looking for isn't going to exist.
2) While timing is a huge part of the test, that doesn't mean you should constantly do full timed sets. For one thing, that doesn't leave enough time for problem-by-problem review, which should be how you spend most of your time. For another, you can get a better sense of how to handle timing by doing short timed sets and then looking at how you spent your time. Which problems ran too long? Were there problems on which you could save time? If you guessed and moved on, did you make the right decision?
3) Most of your verbal timing problems are best targeted by working to make your process more efficient on each verbal type. How are you spending your time? Are you able to predict an answer on CR and RC questions? Are you approaching SC efficiently, or are you getting stuck on difficult or irrelevant issues? Again, this kind of growth comes from careful review of individual problems, not just repeated timed sections.
Good luck!