The two candlesticks, are not two churches. There is nothing in the Bible about two Churches. Furthermore, "candlestick" is not what a lampstand was in Hebrew times. The Jews of Jesus' time did not burn candles made of wax with a wick. They burned oil from some resevoir channeled upward by the capillary action of fluids through a tube to the opening sufficiently away from the resevoir so the flame would not ignite the rest of the oil.
In Zechariah 4, there is one bowl of oil being supplied by two olive trees. The olive trees are said in verse 14 as a means of final explanation to be two people who serve the Lord. The lampstand in Zechariah 4 has seven "channels" coming up from the bowl, which make for the seven flames, or lights Zechariah sees.
Directions for making the Hebrew lampstand in the Temple are spelled out in Exodus 25:31-39.
Those instructions are described as being carried out in Exodus 37:17-24.
The lampstand would have three arms coming off the central stem, which would have a linear tray and several tubes coming off of that which would then be lit.
When Solomon built the first Temple, ten lampstands were made, and five put on each side of the inner room, north and south sides respectively.
In the second Temple and the Herodian Temple, there was only one lampstand.
Revelation 11:4 is the only place where two lampstands are described. Being synonymous with the olive trees that supply the oil for the lamps, I have to wonder if the distinction we would make between the bowl and the "lamps" is being blurred, and because Zecariah's vision was a Heavenly vision, just how accurate Revelation 11:4 is. The question I have is whether we make too much of this equation where the olive trees which supply the oil are also described as the lampstands to say these two people actually represent two different lamps as we are want to do being technically minded, or whether by supplying the lampstand as shown in Zechariah, the essential source for the light is not counted as parts of the lampstand so as to be called that in the plural.
We are dealing with a non-scientific culture when we read the Bible, and we have to keep in mind that they were not as specific as we would be. For instance, the "hand" would include the wrist, and part of the lower forearm in their culture with no distinction like we would impose. Thus the nails the Romans used to crucify Jesus could be inserted just above the wrist between the two forearm bones and they would still call that the hand. Such a placement would support the weight of the entire body, while piercing the palm would only result in tearing the hand up and the body would drop from such a pinning.
Second point:
The time these Two Witnesses prophesize is 1260 days. The "for" is an addition in translation which is allowed, and doesn't change the meaning of the text.
However, it is not said to be the time of the Great Tribulation. In the Olivet Discourse of Matthew 24, Jesus said the Great Tribulation began at the (midpoint) abomination and that that time was shortened. Having it run the whole of the rest of the one 'seven' is not justified by the text, but I am continually amazed how many hoops some people will jump through in order to "stretch it out" that long. Ergo: the Great Tribulation is not 1260 days long.
The Great Tribulation ends when the Day of the Lord begins with the sun/moon/star event of Mt 24:29. Since no one knows when that Day arrives, no one can say just how long the Great Tribulation will last. I think it is the test which will come upon the whole world, from which God will tereo ek - watch out - for the Elect, who will not be fooled into worshipping the abomination (talking image of the anti-Christ erected by the false prophet in front of the curtain in the Temple which remains to be built) but who will almost nearly be wiped out by the dual effects of the Great Tribulation: martyrdom or starvation. Not all the Elect will die during the Great Tribulation as Paul says that some will be lifted up (the rapture) on the Day of the Lord.