I have a Samsonite Termo Young 85cm case
I have packed either a TSR27 or a TSR30 into it.
There is a bit of a knack to getting everything to fit especially with the TSR27 with it’s bolt on and not quick release wheel due to the extra length.
Not sure if a foam cut out would help. I use dropout “savers” in the forks and rear. An old Karrimat cut into thirds and plenty of pieces of the grey foam pipe lagging round the tubes (this needs replacing regularly). I have also cut a piece of aluminium tube which goes over the separating bolt between the frame for extra support.
This leaves plenty space for 10kg of clothes / folding helmet / cycling shoes if using the 32kg weight limit for flying.
Just a couple of weeks ago I managed to fit my ARCC Innovations converted TSR27 into the above case to travel to Majorca and back. Though this did need more dismantlement than for a normal TSR27.