Well, if tramadol is still giving you a decent buzz maybe you should just stick with that for now, because once you start delving into oxy and the stronger opioids tramadol won't cut it anymore. I'm sure you already know that this is a dangerous path your headed on, and that you should never get into the habit of using any opioid frequently, so I'll spare you the life lessons... Expect this valid point to be brought however when asking a question like this, be careful. If you do decide to try oxy I agree that 10mgs is a standard first dose.
The thing is, when I first started taking opioids I actually preffered tramadol due to the incredibly cheap price, ease of availability, and most of all the fact that it lasted almost twice as long as oxy... for this reason I really recommend you hold off on moving up the ladder so soon. Tramadol still has alot more to give so I wouldn't be so quick to spoil it so soon.