We used a second by second round and it worked well. Maybe slow at times, when there are many combatants, but very cinematic. There was a standard time for each action taken directly from converting % of action in a ten second round to a number of second. E.g.: 90% activity = 9 seconds. It could be then modified with your Qu bonus for physical actions or a combination of SD and In bonus for mental actions (spell casting). The length of the weapon is also a modifier (and why not another one for the AT?). We were still limited to one spell per ten seconds (to avoid over casting of instant spells).
When two combatants would hit at the same time, both would roll and apply results. You can end up having the two being incapacited after that!
I know the bonus used give an edge to some characters' classes but this was agreed upon by all the players.