A couple of beginner questions... Profile sizes and cutting area size.

[Voicecoil]

Quite right, but one thing to consider is the common layout for drawing packages on computers is with X horizontal and Y vertical on the screen. This makes the visible drawing area 'landscape' rather than 'portrait' and it makes sense to match this to your machine for those times when you are drawing layouts that are the full size of the machine bed.

Or you can always buy a portrait monitor if the visualization gets too hard!

[Kitwn]

Or you can always buy a portrait monitor if the visualization gets too hard!

You can do that for sure!
What I actually did a few months back was buy a monster 32 inch 2560 x 1440 monitor which provides so much drawing area it's amazing. Soooo much less scrolling about and zooming in and out than I had on the weeny little 21 inch 1920 x 1080 monitor before. The difference is more than I expected and was well worth the not-as-much-money-as-I-thought-it-would-be.