We take it for granted that you've installed O/H feeders before.
If not, there's some learning to be had.
1) Robust anchor points
2) Weather factors (wind, icing,...)
3) Getting up there and working safely (bucket truck?)
4) Crew size
5) Clearances (local rules dominate)
6) Building entry
7) Are you in a mandatory Underground zone?
(Prior installations can be deceptive. The AHJ can insist on underground (new) feeders based upon (recent) local zoning. Out my way, O/H feeders are prohibited. Only the Poco has O/H transmission lines.)
A mere seventy-feet of PVC would have me going underground -- not overhead -- unless the ground was brutal. I'd just rent a trencher.
Electure: Thanks for the pics, they are worth 1000 words.
Most important is a chat with the local zoning & AHJ as Tesla also mentioned. O/H is allowed in some situations here, but unusual. Some fall in Rehab, some are 'temp' to restore site lighting, pending permanent repairs.