I'd suggest that there is absolutely no need for a washaid as you are processing film, not baryta paper. If there is no paper involved then there is nothing to absorb much fixer and it's by-products.

If you don't use an acidic stop-bath of some sort then it is most likely not a disaster for your film, many people prefer water and it is sometimes necessary for particular processes, but note that the manufacturers usage limits for the fixer assume a working stop-bath. You may want to half those fixer-capacity figures.