How to control the precison of a table that has varying number of columns in writetable?

This is my table:

T1 = table(A, EXP, CRU, STA, CAS, NIS, SAM, ... );

If the # of columns is set, I would be able to specify the precision of each column as something like this:

formatSpec = '%s %d %2.1f %s %10.4f %8.3f\n';

and then use the below command to write the table to a txt file:

writetable(T1, 'Table1.txt', formatSpec, 'delimiter','\t');

The problem is that my table can have varying number of columns. If a column only contains NaNs, it will be dropped using the below command, for example:

T1.EXP = [];

In this case, how should I specify the formatSpec?

Many thanks!