The timetables for the revised services due to start on 31 March have now been published on the Traveline website. I have extracted the information from that site and links to all the new times can be found on the Timetables page of this website.
Further details of the changes on the First Bus Tinner routes have become clear. The T1 service continues to run between Penzance and Truro via Camborne at a half-hour frequency on Monday-Saturday daytime. The St Ives to Truro service also continues at half-hourly intervals but half of the departures will be branded as T2 and will continue through Truro to St Austell, replacing the current 27 service, whilst the other half of departures will be branded as T3 and will continue through Truro to Newquay and will replace the current 91 service. There will be just a 5 minute layover in Truro bus station which may be a bit tight!
The summary of the changes can be viewed here.
There are many other timetable changes. They are detailed on the Timetables page of this website.