I know you have mentioned not being able to choke people with this but how about some ice in the mouth, freeze someone's saliva to stop them casting.

Create a Bridge? on an area of water you should be able to create an ice platform in 5ft chunks which you can walk across. It depends on how you interpret the "Freeze for 1 hour" and "Only two effects at once" rules, if that's after an hour or when you stop concentrating it instantly melts then you will have to make it as a floating 10x5 chunk just dropping the last and creating a new section each round. If you read that as once the spell stops affecting it the laws of thermodynamics take over then you could build an ice bridge which would probably last a few hours. (Also I am picturing Magento making a bridge while walking across it from the first X-Men film as i type this :P)