I would drop the tramadol dose a bit, as it it getting close to a dangerous dose - tram should potentiate the codeine quite well, and 300mg of codeine (assuming you have a tolerance, yeah?) shouldn't be too risky.
The combination of 300mg codeine / 100mg tramadol seems like a safer bet to me - but I always erred on the side of caution with tramadol.
Codeine doesn't seem to be much use when it comes to redosing, but my experience with adding small/moderate doses of tram with other opiates was usually equal to more than the sum of its parts (if that makes sense?).
YMMV and the usual disclaimers...
Play safe !