4-5-1V seemed to get de-powered 5 or 6 seasons ago for me - I do still use it on occasion (mostly if the oppo is playing 3 DCs), but generally only as a defensive counter-attacking formation. Note, I have found myself playing defensive-counter a lot more than I used to as I've moved up the leagues.

Generally it's my experience that a lone striker really struggles against a back 4, unless paired with an AMC - and an AMC isn't worth it if there's a DMC in place. I have 1 each of ML/AML, MR/AMR, AML/AMC and AMR/AMC in my 22 so can adapt to most requirements.

My defensive squad consists of 9 players, 2xDL/DML*, 1x DR/DMR, 1x DC/DL, 1x DR/DL, 4x DC/DMC, so I'm geared up to field a 4-man and a 5-man defense daily, it's really rare that anyone either misses out on playing or has to play twice in a day.


*I've got 2 good ones currently, will be going down to 1 and getting another DC/DMC once one of them gets too old

My rules of thumb when setting up for a match are:
-Always have at least 1 more defender than the oppo has strikers (if he only has 1ST you can get away with 3W or 3N and put red arrows on either the wingbacks or the DMC if you're using one)
-Always play a DMC if the oppo has an AMC
-Don't play an AMC (or possibly play 2 of them) if the oppo has a DMC
-Use long passing against a flat formation, mixed otherwise. If you're getting 80% possession due to an opponent's illegal/out of position formation it's worth playing long ball - I have a theory that often the "bonus" possession gets wasted playing tika-taka in midfield otherwise, and if you can give your strikers the ball a lot they'll get through eventually
-A DMC is really useful against 3MCs, as otherwise every now and then one breaks forward and gets a shot off from the AMC zone
-Only use down-both-flanks passing if you are fielding more wingers than the oppo. Use through-the-middle with narrow diamond (and I guess 4-3-3 - I only have 3 strikers in my squad so have never tried it).