My feeling is that CTL is the nearest thing to gasoline post-peak, and so it will come into play. However, I also suspect that it cannot be ramped up nearly as fast as oil production is capable of depleting, so there will still be some net depletion over-all. CTL, oil sands, etc, are basically ways to lower the depletion rate (which is a good thing!)
The main reason that I believe in a "Bumpy Plateau" rather than a HL decline for TOTAL world oil & equivalents is because that coal to fuel and NG to fuel schemes will come on-line.

However, the time constraints are such that the unconvential sources will always be running behind (hence the bumps) declines in convential production.

Diesel is preferred for coal > fuel (C-H ratio, gasoline is more of a stretch).  Gasoline from NG (same reason).

Plans for more than small projects are still years away from a "Financial Decision Point".  Figure eight years from "FDP" to operations.

Water is a limitation out in MO.

A multistage plant using high sulfer Illinois coal (max buildout 200,000 b/day of diesel) is building Stage 1 (from memory).  No water problems there.

Carter wanted to build these plants 32 years ago.

TERRIBLE for GW :-((