Depending on your needs, which I can not tell for you, be discriminating applying the patches you talked about. The CSSU team deserves all respect for what they are doing and I admire their work, but for me, I don´t need even half the things that are in that package, and some of the things that are in there made my machine a little bit unstable. That does not say anything about your machine. Your n900 really behaves like a pc, by which I mean they differ from machine to machine. I run power kernel 42, because it runs more stable on mine, and it doesn´t include the usb-host patch, which gave me some trouble in the past charging my phone. You will have to find for yourself which one runs best on yours.

If you overclock, you should be aware of the fact that it is, very much as Jedi already pointed out, a low-level form of tweaking. A clockspeed of 1100 causes problems, for many, many people.

In short: I would reflash, run the power kernel that suits you best (experiment!) and for the rest do not install "programs" that make low-level tweaks unless you are 100% certain it does exactly what you want it to do.

The only tweaking-thing I have installed apart from the powerkernel is QCPUfreq, which allows me to overclock on a session-basis, meaning that if I reboot, the overclock speed is gone. I don´t reboot very often, so if I do, I start up the program and set my preferred speed. I mainly overclock when I watch a movie on the phone and have it plugged in to a TV set, or when making music, using SunVox. Apart from that, I use the Smart Reflex function from QCPUfreq, which does wonders for my battery life. Smart Reflex did not work for me though, when I first ran it. I had applied way too many tweaks and been playing with things, so it would simply cause a reboot. Lots of people have that problem. But after a reflash and using power kernel 42 Smart Reflex works 100% stable for me. I do recall some reboots though, when I was running kernel 47. 48 I have not tried.

Stay away from the Karam script. Learn to use the terminal. That´s really the only thing you need and it comes pre-installed with the phone.
Reflash and see how you like your "normal" stock settings. Apply tweaks and patches manually, by simply searching for them on the maemo site.

To do that, go to google.com, type

and hit enter.

Learn. And enjoy the control you have over your phone.

By the way: know that your phone is a true linux machine. If you use the terminal to carry out tasks, it pretty much behaves like any linux computer would. That means you are not limited to talk.maemo.org, if you are looking for a solution for some problem. Often, a general linux site will be able to help you out with answers.

I don´t need more power on my phone than what I get from those two things, QCPUfreq and the power kernel. People here on the forum seem obsessed with CPU speed and such. For me, I don´t care. I do things on my phone I could not have imagined 15 years ago and they run smooth, even when I run the phone @600Mhz. Treat your phone as you would your desktop or laptop, but see it as it´s little brother or sister. If you run 20 programs on your desktop machine, it will slow down. So will your phone. And just as your normal computer, the number of widgets, the number of shortcuts on your desktop, etc. will determine how fast your phone reacts. If you tile your desktop with a shortcut or widget on every pixel available, on all of your desktops, things will slow down.

Above all: Enjoy the learning experience. Perhaps you´ll want to install Linux on your desktop one day.