Ok your call options' losses is limited already; it's only going to be your purchase price which is $600*100*0.5= $30,000 (I dunno how you get $29,000) assuming you are going to hold it until expiration and it's going to expire worthless otherwise there is always a chance that the underlying stock will go up and you will be able to make some money. If you really feel that there will be no chance that the stock will go up, then you should sell it now at 0.30 and at least your loss will only be (0.3-0.5) X 600*100 = $-12000 otherwise you are going to lose out on price and time decay even if the underlying is gaining value.
The only few things that you can do to potentially "limit your losses". One is to buy puts so if the underlying goes down in value, you can potentially earn some profit but this combo would only work if the underlying's price moves a lot either way, i.e. has high volatility otherwise you are still going to lose money and even more money potentially but not infinite losses though. Another is to try to short the shares when the share price is higher than the strike on your call options if you really believe that the shares will go down in value in time, then this might be worth the shot. When worse comes to worst, you can always stop out on the shares and cash out on the call option. Again, not a guarantee of success but will not result in infinite losses either.
Not sure what kind of scenarios you have tried in the IB software that resulted in infinite losses...
