Unverified numbers:

I think you'd need about 2000-2500 to leave in order to make left seat of a 737/AB320 from the bottom of the list. So based on these figures you'd be looking at about a 7-8 year upgrade if age 60 remains. Add about 3-5 years if it goes to 65. The much ballyhooed "geographical fence" is a big unknown and could make the time shorter if you're an Eastie and/or you're willing to take the E190 C/O seat. Good luck.

The retirements are very heavy on the East. Here is a list of retirements per year from each side based on age 60:

Year / East / West / Cumulative

2007 / 228 / 43 / 271
2008 / 177 / 46 / 494
2009 / 232 / 47 / 773
2010 / 194 / 52 / 1019
2011 / 246 / 44 / 1309
2012 / 267 / 65 / 1641
2013 / 283 / 51 / 1975
2014 / 289 / 77 / 2341
2015 / 289 / 69 / 2699
2016 / 292 / 68 / 3059
2017 / 255 / 66 / 3380
2018 / 261 / 85 / 3726
2019 / 209 / 78 / 4013
2020 / 222 / 88 / 4323
2021 / 168 / 90 / 4581
2022 / 165 / 94 / 4840
2023 / 148 / 77 / 5065
2024 / 118 / 92 / 5275
2025 / 97 / 94 / 5466
2026 / 103 / 77 / 5646
2027 / 109 / 68 / 5823