It sounds like you don't want to rush things at the end. You can have longer blind levels near the point at which you want it to end (the 5% level). That will give you more play. But as stated above, don't stop raising the blinds. I wouldn't say the tournament will never end, but there is no telling how long it will last.
2+2 poster PFAPFAP created a great cheat sheet for structuring tournaments. Click the images below for a larger version.
You'll have to adjust these for your larger denom chips.
On the first page you choose your stack size and the length of your blind rounds. You do this based on what you already should know: how many players you have, and how long you want the tournament to last. For each combination of these, there are three choices of stacks and lengths.
This is a great starting point, but you can tweak this as you like. If you add more chips than recommended, of course your tournament will run a little longer. For example, with the same blind lengths, going from 4K to 5K might add one or two blind levels.
The next page is the blind structure, which is the same for every tournament. They are the ones used in the WSOP.