I will be building a greenhouse and considering which will be stronger: 1" rigid conduit (1.315 OD) or 1 3/8" 17-Gauge Galvanized Steel Top Rail.
The top rail is half the price so it is attractive. Is the top rail 1 3/8 OD? If so, these seem comparable in terms of size. Would fittings for one work with the other?
Is one of these a better choice for a greenhouse for other reasons? Top rail end caps seem to be the connectors of choice making trusses with top rail and are far cheaper than the expensive fittings for rigid conduit.