switch to gaussian seeder to test updates in MR !31636
As above. Switching to Gaussian seeder to allow checks on CPU use in high pile-up following optimizations. Plan is not (currently) to stick with this option longer-term unless a) the CPU performance is reasonable b) the physics performance shows a noticeable improvement. Point b) can probably only be assessed at a later date, and so this change will likely be reverted once monitoring plots have been checked.