These pills are extremely dangerous. The average dose in them (1.2 to 1.6mg as described above) is nearly in the lethal overdose range for non-tolerant users (and could be lethal for some nontolerant users). That's just one pill. Also as mentioned, they are not consistently dosed at all and some have been found to be many times the lethal overdose range (again, in a single pill). And that's when eaten.
I would eat it if you must take it at all. It will last longer that way, and peak plasma will be reached in a longer time which reduces the risk of withdrawal. That said, a single dose of fentanyl (unlike the patch which gives you constant doses for 3 days) is very short, even eaten. Quite a bit shorter than oxy.
Actually, scratch that. If you eat the whole thing you might just overdose. if you snort little bits of it, or smoke little bits of it, you can titrate your dose more effectively, since you will come up quickly and you can then judge if you need more. Start with a small bit crushed from the pill and work your way up. Consider that each individual pill might be very different in strength.
Fentanyl is so dangerous, largely because of how inaccurately it's dosed. There are hot spots even within individual pills/bags, from being unevenly mixed. Pharmaceutical pills are made professionally and you ca be sure they are evenly dosed due to the presence of effective binders, but black market fentanyl has no such guarantee. If you could be sure of just how much you were taking, we'd have a LOT less overdose deaths.