CT shirts in 15.5 neck jump from 33 to 35 sleeve length. So if you are 34 inch sleeve length you need to buy the 35 and have them shorten it at CT by an inch.
TM Lewin shirts go from 33 to 34.5 sleeve length (for 15.5 neck). Not sure about other neck sizes and what sleeve lengths those come in.
This is only for slim fit non-iron shirts from both these companies.
You can sort both websites shirts by what you are looking for...neck size, cuff type, sleeve length, non iron.