No expert here by any stretch but I think the key for me is to use whatever technique works best on the job at hand. Something thin? probably a good whack with a pricking iron and youre ready to stich, More typical projects, stitch mark (pricking iron) then I normally use a diamond awl as I stitch.
Ive done a few knife sheaths with 5 layer welts and used a diamond awl in a drill press(not running) to punch thru.
Lots of different ways, I think everyone ends up doing what gets the results that they are satisfied with.
I tried drilling on a couple projects and didnt like what I was seeing in the end result, not for me.
Thread; I really like tiger thread, Have a good bit of the thread from Maine Thread but to me it just doeset feel as nice as the tiger thread; at the moment Im using both