And at the bare beginning I got the window saying "android.proces........" force closed that appeared for, maybe, a second and disappeared with no interaction.
Pastebin f**ked me up so I attached logcat to the message.
Well, the bucketload of ANRs (Application Not Responding) both you and the logcat report would suggest that your card is basically too slow for INT2SD which has the entire /data (including Dalvik cache) on the SD, especially in combination with the resource-hungry beast that is Sense.
I have a class 10, and it seems slower than it should be, though those are all the issues (if you can call that an issue ) I'm experiencing. Class 6 should be enough, though some people have reported problems with C6 being too slow as well, yet it works like a charm for others. Probably better to ask someone who has more experience with SD performance since I have only ever used a grand total of 3 cards with my 2 Android phones (two of those came along with the phones) Good luck!
This is the INT2SD thread for Sense ROMs and their developers and users.
INT2SD thread for AOSP ROMs
Disclamer: I am not responsible for anything that goes wrong.