Well all I can say is do what your comfortable with, like I said in the beginning. I recommend other things before trying to extend my pinky out because it slows me down. My way to play your example would be...

[u]Your example[/u]

|
|
|
|----------------------------8
|--------------7--10--12--
|--5--8--10

[u]How I would play it[/u]


e-----------------------
b-----------------------
g-----------------------
d--------------5--7--8--
a--------5--7-----------
e--5--8-----------------
i p i r i r p


Drop the 10th down a string. To me there is no clear reason to stretch for the 10th fret. But if you feel you need to and your comfortable with it by all means do it.

4 note per string scales have a tendency to climb the fretboard, as you can see from the previous example. Sliding shouldn't slow you down, and actually your gonna want to get used to it if you want to solo in the near future. It will play a HUGE part in solo technique, especially in metal and blues solos. You'll see this alot [tab]---/12-etc.[tab]. Here you slide quickly up to the 12th fret before beginning the lick afterwards (Jimi's solo's are filled with them). You'll see this too [tab]-5/7-etc.[tab]. I remember learning a metallica solo a while back, where one slide was a 32nd note and the rest of the lick was in 16th's, so the slide had to be twice as fast as the lick. If your sliding is sloppy, start practicing it cause you'll need it. Just letting you know ahead of time. ;)