[Radioroslyn]

Value isn't critical you could go as high as 47mfd or so. Back in the 1920's and 30's electrolytics where expensive to make so most of the filtering is done with inductance. If you look at diagrams say of a Philco model 87 the filters are like 1 or 2mfd and two or three chokes. Very important to observe polarity and voltage rating. 450v for this one. Philco in the '30s some times would use a small paper cap across the filter choke a help resonate L/C to 60cy.
Have Fun & happy new year!
Terry