The problem is your trying to stretch it to 'great white throne judgement' which Daniel 12 says nothing about. The 1260 years are the time of the Papal supremacy which came to be called the Dark Ages and finally it received its 'deadly wound' when Napoleon sent his general to take it down in 1798, and then the time of the end would begin.
Here is a very indepth study on this...
"The phrase, “time of the end” is unique to the book of Daniel.18 The prophet was told that his visions would be “shut up” and “sealed” until the “time of the end,” after which “many” would “run to and fro, and knowledge shall be increased” (Dan. 12:4).Because this increase in knowledge relates specifically to an understanding of Daniel’s prophecies, the “time of the end” evidently refers to the final period of history leading upto Christ’s return, during which the faithful would gain a deeper understanding of Daniel’s visions. As discussed above, two “how long” questions follow Dan. 12:4, both of which are answered by prophetic time periods. The first time element of 1260 days follows the first “how long” question in reference to the “end” (Dan. 12:5-7). Since the 1260 days equate to 1260 years that extended from A.D. 538 to A.D. 1798, this termination point would witness the arrival of the “end,” or “time of the end.” Daniel’s prophecies have been unsealed since the year A.D. 1798, and knowledge about these prophecies has increased since that time. Furthermore, the time elements of 1290 and 1335 days that follow the second “how long” question are also given in reference to the sealing of Daniel’s prophecies until the “time of the end” (Dan. 12:8-12). Similar to the 1260 years, these two time elements help to explain when the “time of the end” would arrive and when the unsealing of Daniel’s prophecies would take place. Since the 1290 and 1335 days equate to 1290 and 1335 years and concluded in A.D. 1798 and A.D. 1843, this timeframe is to be identified as the time when Daniel’s prophecies would be unsealed and understood by the faithful. This understanding would especially focus on unlocking the meaning of the 2300 years of Dan. 8:14, a point that will be discussed in more detail below. Daniel was told that, during this time (the period between A.D. 1798 and A.D.1843), his prophecies would be understood and speak truth to the people, thus“ standing in their lot at the end of the days” (Dan. 12:13), i.e. at the end of the 1260,1290, 1335, and 2300 prophetic days, which equate to literal years and met their fulfillment between the years A.D. 1798 and A.D. 1844."
