I don't know those particular lenses though no doubt someone will, but I'd say they will be fine. I haven't used a wide field Ektar but I do have a 207 Ektar which is a superb lens. About the only thing you really improve on with newer lenses over the best quality older ones is the coatings, and that will really matter only with backlighting or strong light sources inside or close outside (or relatively close, depending on the coverage of the lens) and even then it's mainly a loss of contrast so in black and white you just print it on harder paper. More modern shutters are also more reliable, less likely to need work and easier to have serviced but if the older ones (like on my 203 Ektar) are working ok they're fine.

16x20 is loafing for 4x5. That's only a 4x enlargement. The equivalent in 35mm would be a 4x6 print. Either of the lenses should resolve more detail than you'd ever see in a 4x enlargement.