A walking jacket would be perfect for your kitty.
I have used a figure 8 harness with past kitties but it is easy to escape from.
We tried an H harness when we first got Quasar but it was easy for him to escape and he grew out of the kitten size quickly.
We moved on to a kitten size jacket that we had to upsize once to an adult size one when he was about 10 months old. Since your kitty is already full grown you could use an adult one right away.
The makers of jackets, Mynwood and Happy Housecoats, make their jackets to fit according to measurements clearly outlined on the websites.
These jackets are highly adjustable due to the length of Velcro strapping that secures them closed. The most important thing is to make sure they are securely snugged tightly on your cat. Kind of like tightening the girth on a horse saddle, it is nearly impossible to accidentally make the jacket too snug. If it is loose, the cat can, with a struggle, back out of the jacket and escape.
The jackets are washable and dry quickly so rinsing out the cat hair is simple.
Happy wardrobe shopping!