If you want to trade spreads Reg-T margin is fine. Lots of folks here doing that. http://www.interactivebrokers.com/en/index.php?f=marginnew&p=opt
I would suggest to change the broker immediately. Until now I have not hard if a broker that allows buying options and does not allow selling them.
do not use stop loss in option. first option is just for very short-term trade, at most in days, most in hours. second option chart is twisted fact: time declay plus premium pricing, if a stock drops and then back to the same price, your option noramlly will not do that, your call most likely end up a slittle bit lower. when the time remaining in option becomes less, this twist will become more servere. particularly toward expiration. if you trade far foward option, that effect is neglectacble. but often those far forward ones are not liquid. stop loss is a very bad strategy in other trading too. better choose to ride adversary out. in option, ride it toward worthless. stick to it. most time, those looks no bid thing fly in blink of eyes, so hold it whether it looks wrong or not. that is what my strategy. this week, I bought AAPL 465 calls a little bit early, but it went down so hard, my calls almost at some point, menced me 80~90% down, but I choose to hold, the patience paid me off. until the expiration, before expiration, anything happened, just ignore them. take the risk and ride. that is the fun part of option trading. the worst case is worthless, that is it. if the market keep going aginst you, your risk is limited to your option premimum. that is the beautity of option trading.
I personally always place stops based on the stock price. If the stock breaks a support level and i am long i'll place a contingent order. Vice versa if i am short. Sell option if stock price equal to or lower then specific price. My option trade is contingent to price of stock.