If the Great Year lasted 26000 tropical years, and if the begin and end of a Great Year saw the sun and moon and plantes in conjunction, then I would assume that someone could tell me the Mayan definition of the synodic Venus orbit or simply Venus year, but apparently nobody can, so I calculate the numbers of Tzolkin and lunations and Venus years in the Great Year with my own methods and formulae.
42 tropical years are 59 Tzolkin. Multiply the numbers by a factor of 619 and you get 36521 Tzolkin for 25988 years. Add 3 Tzolkin for the remaining 2 years, starting value of the sequence
3/2 (plus 7/5) 10/7 17/12 24/17 ... 59/42
and you get 36524 Tzolkin for 26000 years.
405 lunations are 46 Tzolkin. Multiply the numbers by a factor of 794 and you get 321570 lunations for 36524 Tzolkin or 26000 years.
240 synodic Venus orbits are 539 Tzolkin. Multiply the numbers by a factor of 67 and you get 16080 Venus years for 36113 Tzolkin. Remain 411 Tzolkin. 411 times 240 equals 98637. 183 times 539 equals 98637, practically the same. Together you obtain 16080 plus 183 Venus years for 36113 plus 411 Tzolkin, yielding 16263 Venus years for 36524 Tzolkin or 26000 years.
A Great Year of 26000 tropical years 'equals' 36524 Tzolkin or 321570 lunations or 16263 synodic Venus orbits (mistakes in 500 years: Tzolkin conversion 1.1 days, lunar conversion 2.8 days, Venus conversion 0.12 day).
Definition gained from the Tzolkin conversion: 25 years are 9131 days, 25 regular years of 365 days plus 6 leap years of 366 days, according to the sequence
2922/8 (plus 6209/17) 9131/25 15340/42
15340 days are 59 Tzolkin for 42 years, from the sequence
3/2 (plus 7/5) ... 59/42
Mathematics may be regarded as the logic of building and maintaining, so it is hardly surprising that the pyramid builders of Egypt and Mesoamerica and ziqqurat builders of Mesopotamia used the same mathematical tools, additive number patterns and sequences that have a certain affinity to the piling of block on block and brick on brick.