Indeed, it does not take less time to pronounce the 'es-' of "esse" than the 'stri-' of "strigo." If you pronounce "esse" correctly, the 's'-sound will be quite geminated, twinned, lengthened such that the first syllable of "esse" will be at least twice as long as the first syllabe in "strigo." You may be pronouncing the 'i' in "strigo" a little too long (something that most Italians, for example, are not capable of doing since it runs counter to the above stressed-long-syllable rule of their tongue as I outlined above).For instance, with word like Ä›sse and strÄgo (it took me a while to find such a word in Latin), where I'm pretty sure that the first syllable of esse takes less time than the first syllable of strigo, why is es "long" but stri "short?"
If you'd like, we might arrange a brief conversation on Skype; I'd be happy to show you a few things about Latin pronunciation that are quite difficult to perceive without a frame of reference, that is, without hearing a speaker speak them. That offer goes for anyone, actually.