I have a provari with the 18490 batteries and they don't seem to last long enough. I get about 6.5 to 7 hours of vape time and that's just not long enough. Should I just buy the extended cap and 18650 batteries or just a couple more 18490 batteries? Is the extra vape time worth the extra length and size and money? How much longer will the 18650 batteries last? Sorry about all the questions thank you far any advice and opinions!!!