Hi Salman
Good question... Have to see its a nice collection already. I also really like the AP RO and actually prefer this for the ROO. Thats my taste. Have a mid-size myself
Extention of your collection... well:
Depends on how to extent. You have mainly Rolex, one AP RO and one chronograph Heuer. So I would go for different approaches:
A: Extend your chronograph selection:
-Add a Omega Speedmaster, pre-Moon
-Add a Zenith El-Primero vintage
-Add a Rolex (would siut your Rolex part) Daytona... many different models to selcetc from. Joes 6539 is a nice choise
Or a 6263 or a ..? Up to money and availability
-If you like, add a AP ROO Chronograph
B: Extend on the Rolex
-1655 Steve McQueen orange hand Explorer
-1680 Sub red
-James Bon Sub.... my favorite..6538...
Cheers
Hans