To be honest, I am at a bit of a loss as to the best direction to take with the tailoring.
I'm not a tall guy, nor am I short - I am about 5'8.
I'm a 32"-33" waist and really broad in the chest/shoulders. I cannot remember the numbers exactly, but my chest is about 100cm or more.
I've tried shirts in size M and they're either too slim, or most of the time, too tight across the back/chest. To the point where I struggle to touch my elbows together if that makes sense. However they fit in the shirt length and sleeves.
As I sit down at a desk most of the day, tightness across the body can be uncomfortable s
o I try to avoid that and end up buying size L shirts. And as we all know, they are too long in both the shirt and the sleeve for me.
Further to this, i'd love to be able to layer as it's plainly obvious how it transforms a fit. And I would say in many ways hides some of the issues. The reality is that I live in a warm climate and it's not always possible. I actually had dinner with my sister who just arrived home from living in London for 4 years and she was saying that she doesn't know how to dress for Australia anymore. She'd become so used to layering and the styling benefits that come from it that she was going to have to get used to simply chucking on a little top and skirt again.
Start by hemming everything that needs to be, jeans, shirts etc. Some of the shirts you have would also be benefited by shortening sleeves. You'll need to decide which shirts you will wear tuck/untucked only. A 7" drop isn't crazy abnormal, have a think about the shapes of your shirts and whether some neednslimming or not. Take note of the WAYWN posters that have a similar build.
Layering is hard to do in Aus mate, wait until our "winter". I just try to stay cool in summer, lots of linen and lightweight cottons.