I mentioned before how the converter took advantage of EU3's extra techs. For reference, here's the last few techs they defined and the starting years:

technology = { id = 62 average_year = 1805 }
technology = { id = 63 average_year = 1807 }
technology = { id = 64 average_year = 1809 }
technology = { id = 65 average_year = 1811 allowed_ideas = 12 }
technology = { id = 66 average_year = 1813 }
technology = { id = 67 average_year = 1815 }
technology = { id = 68 average_year = 1820 }
technology = { id = 69 average_year = 1830 }
technology = { id = 70 average_year = 1840 }
technology = { id = 71 average_year = 1850 }
technology = { id = 72 average_year = 1880 }

That was from the government list, so completely useless past level 65. The other tech areas provide the usual incremental benefits right up to the end, so I'd recommend something similar.