I agree, the 'thumb' version of LT cast on (or 2 handed version is what I call it) isn't tight at all. It just depends what you're used to. It's the way I figured out how to LT cast on because I couldn't do it the one handed regular way. It all takes practice - cast ons, knit and purl sts and all the rest.
It's almost always a struggle at first and if not at first, then at second. Remember that there's often more than one way to do whatever you want to so: cast on, knit, purl, etc. Try different ways until you find something you like or that makes sense to you.