Both Paul and Greg are quite correct. But first you must evaluate whether collecting mega data is worth it. The only real criteria is that your signal to noise of the dimmest bits of the image you wish to show or record is above at least one or far better, two sigma.
When I was working out what to get for my 'new' system I did not compromise anywhere. I wanted to do very deep NB of dim objects at a moderately wide field. I could most probably spend the rest of my life trying to get the detail in the Vela SNR and the two Magellanic Galaxies and still not get it anywhere near perfect.
If you take as a starting point a very fast optic then the best quality largest 3nm NB filters are a no brainer. All else also follows e.g. a very low noise camera and best focuser available.
With 16 minute exposures with any 3nm NB filter the signal to noise is still improving even after thirty exposures. I would say that double this (60 exposures or 16 hours) is still worth doing.
In a target rich place such as the LMC it is surprising what pops up.
This is about twenty four hours of total exposure. 9MB
http://d1355990.i49.quadrahosting.co...70_NB_HP_N.jpg
Bert