I've got one or two houses where the frames are terrible, I tried wfp on them two times, last time it was still really badly leaching from the frames (25 year old conservatory, with black frames, and degraded seals) and then rest is really badly oxidised painted frames. I told the lady this, but she wasn't very happy with it, it's such a job getting them up to standard, rinse rinse, don't touch the top frame etc. A real pain.
So now for downstairs windows, I just squeegee them off. I tried this with just the pure water on the glass, but couldn't get on.
So what I do now is just put the bucket on a belt under the van port, fill it up half way, put a couple of drops of Squeegee off in there, and just do them by hand, so much easier if the frames are in poor quality. Upstairs is still wfp though, no ladders for me anymore, except for access.
Strange, because you can be so fixated on using wfp, and how to make it work on bad windows, that you can totally forget that it's actually 'fine' to just do the bottoms by hand, didn't take me long at all, perhaps even faster (I'm a fast trad cleaner), it's almost like you need to prove that even on bad windows wfp works. It does work, but it takes too long I find, and it's just too tricky sometimes.
I always have my pouch on my belt anyway with wfp, have a sill cloth in there, and one for detailing (quick wipe over the top seal if the drips keep hanging after you wfp'd them), and one to wipe my hands with if the hose gets mucky, so it's just a matter of clipping the boab on. If you half fill it, there's plenty of water in there to do a full semi detached anyway.
I guess sometimes you just have to almost swallow your pride, and then do them by hand, but it's all between the ears, a tool is a tool, the goal is to get a window clean, and use whatever means necessary, whether it's squeegee, wfp, spray and buff with microfibre, it doesn't matter. It was quite satisfying to do some blading anyway, even though I regularly do insides, outside trad is always easier, not being careful with carpets etc.
Anyway, I find that wfp works great on the vast majority of windows, even if they are a little bit milky, but with some you just need to do whip out the old squeegee.
Well, that was my experience anyway.