You can use whatever liquid amount is convenient, then make up the remainder with DME, which is easier to measure.
Also, if you can't get fresh LME, go with dry instead. It has a much longer shelf life. Just make sure you convert the amounts between LME and DME.
I hope my post helped in some small way. If you need to contact me, please use email since it sometimes takes me several days to get back to the forum.