Re the size of this TT. A little bit of additional length can be obtained by allowing the Rails to overhang. Or you could go down the route of the GWR that used to have Extension Bars. There is a good pic of these in use at Minehead in the book 'West Somerset Railway a View from the Past". Thougbas in the realmthing, extension bars may be somewhat cumbersome to use. These allowed a 2-6-0 to be turned as the Table had only be put in to cater for 0-6-0 and 4-4-0 locs. No such problems exist with the current TT at Minehead, 9f's and Pacifices being turned regularly.
JonD