We do 80' of 6", .188 X42/52 all the time with a hoe and two 15' choked slings. Ive seen others pick up same with one sling. If the operator snaps the load it will bend the pipe with one sling.  If the crane is adequate I would at least do a trial pick under controlled situation.  The only assumption here is the welds are to a code other than Farm Code 2013.

120' of 6" is easy with two machines, harder but real doable with one. It's done many times every day but your conditions may (or may not) make it more difficult.

Picking 120' of 6" to a unhindered elevation of 20' is different than landing it at 200' over 220' of structural and in a far horizontal reach. The height you're flying to and the horizontal reach vs. cranes on hand is the real kicker.

As was already said an experienced pipe rigger with comealongs/chain falls and an assotment of chokers can do it easily but depending on the landing spot removing the large array of rigging can become a major endeavor=$$$$.

In the end you have to know the specific conditions on where it lands and the equipment available and plan the pick from there. Lowering in it's super easy, landing on an 80' high pipe rack (with 120' obstruction) it's mo harder. Having two 4100's with 300' of stick and 5 gang boxes of rigging to use it's all easy (if you have decent, experienced pipe riggers on hand), doing it with one way outstretched 30T hydo is a whole nuther endeavor.

So really there isn't enough information to give a semi-decent opinon via the interwebs. A large number of factors come into play in picking longer sections of pipe and you haven't detailed out any of them so far. So no one can really say at this point.

You have to balance the cost of making an additional weld or two (in what may be a difficult to impossible position) against the cost of a semi-complicated pick using the equipment available. It's not a simple decision but it's made hundreds of times per day.

J