The shulchan aruch 531 '2' forbids one from hair cutting on chol ha'moed so that one shall not postpone the cutting until chol ah'moed when he has got more time.
In the following siman the Rema' brings down those that are scrupulous about nail cutting on chol ha'moed for the same reason.
Now,being that the mishna berurah 260' brings down those that say specifically not to cut ones nails before Erev Shabbos,along side the above reasoning that by allowing oneself to cut them on Wednesday he will slowly stop being conscientious about this mitsvah,being that shall he be desperate he will do it during the week,he should refrain from cutting them on Wednesday as when becoming a habit it would minimize in kovod Shabbos.
Although there is an issue of chatzitza in hand washing when growing your nails long that is however only pertaining to washing prior to eating bread which you need not do on a weekday.Concerning the morning hand washing there is no such issue lehalacha. Therefore there is no problem waiting for Shabbos.
However when the nails are so big that poeple,kind of nicely,notify him that his nails are quite long,then we may say he should not wait for erev Shabbos.
The reason being since in hilchos aveilut Y'D' 390' it is said that an avel after his parents may cut his hair after 30' days when peaple are screaming at him already the reason being i guess because of chilul Hashem whenbeing a disgrace in front of people.
More so Rabbi Akivah Eiger says that an avel after 30' days need not wait to hear people screaming at him before cutting his nails since nails after 30' days are disgracefully long to go around with.
Therefore we may conclude that when his nails are reasonably normal looking (as he 'did' cut them within the last 30' days) then because of the reasoning explained at first he should wait for erev Shabbos.
However when his nails are embarrassingly long (perhaps as those the avel after 30' days has) he need not and probably should not wait for erev Shabbos.
