I tend to think it's better to just try and fit the form first, then take the rest of your preferences on board (as in frills or no-frills).
Catboys can be a bit tricky to dress in some outfits because of their height and girth. A lot of what might be consider skewed masculine (i.e., lots of tank gear) can bulk them out in an unappealing manner. Robes and long-coat styles can also drown them.
I'm sure you have quite different criteria as to what looks good, but let me share what I do for my catboys (my main alt is a catboy, I have another two catboy alts and my squadron for my main is half catboy), as a note-comparing exercise:
My catboys use the fireglass leather hoodie (without the t-shirt), or the summer indigo shirt - both may be either gender, but they look awesome on catboys. Use the peacelover's trousers, or calf riders plus the trainers (high tops or calf rider) or rebel boots. It looks good, even if you might find the fact either gender can wear this problematic - my personal preference is to use gunmetal black on the trousers and fireglass hoodie, jet black on the shirt, trainers and boots. I also like the Strife trousers - the length is especially good across the board (and really, catboys look best with length to combat their short height, although this claim is not something I'd die on a hill to defend, because I've found enough ways around it).
If you're tanking, goatskin trews in gunmetal black lower the waistline in a pleasing manner; that plus the fireglass hoodie (no t-shirt version) will show nice arms and some stomach/abs. You might also look at the endless summer attire on the mog station - it's open-shirted for the guys.
Then you might also consider the coeurl talisman/south seas talisman (both are male only). I have my catboy's monk job dressed in the south seas & fireglass trews (though peacelover's work too), and it's appealing with punching gloves as well.
If you want a shirt that's smart, take a look at the Thavnairian wool autumn shirt. It's default colour is questionable, but it's male only. The only issues I can see arising may be the excessive buttons and/or swirly pattern on the cuffs, and being honest, I have this but don't use it. It's not rock and roll enough.
Failing that, the emperor's new robe chest piece might do you well. My husband uses this on his catboy, with the default starter boots and the pagos gaskins (I feel those gaskins skew quite masculine, but YMMV). I think he uses this on all jobs.
I don't know if any of these suggestions will work for you in the short-term at least, but know I am sympathetic to the plight of wanting specific stuff to wear and not finding it - regardless of gender! And if you ever want to visit my corner of Zodiark in November to try and deal with this game's take on fashion, I'd happily welcome you over.![]()