Short Calendar spreads seem to have alot of the characteristics that suite my trading style. However, when I look at equity spreads with say 3-6 months left (for both contracts), the spreads don't seem much more than .05-0.20, even when IV is relatively high. What is reasonable to expect for a credit when putting on these kinds of spreads? Should I be looking out further in time between expiration months, or look at indexes as the underlying? I only want to put on these spreads when IV spikes, and indexes haven't had alot of IV lately.