Even the F214 figures are usually highly inaccurate.
Sometimes, but I've not found this to be the case very often. Whatever I normally plan on the ground works in the air. Any usual variences in wind speed and/or direction don't tend put you far off course anyway, especially if you are attempting to work to a reasonable level of accuracy.
Fractions being much simpler than decimals in such circumstances.
Horses for courses methinks. I like decimals because the (TAS/60) element plugs into other rules of thumb that I will find useful during the IR such as radical interception anticpation, descents etc. Also, if you round to whole numbers or to ?.5 decimals only then the mental math is a sinch. I find it easier if I have say 32 / 2.5 (e.g. 32kts/(150kts/60)) to just mult both by two and divide 64/5 = 13. Personally I seem to find that much easier than thinking 32*2/5 or 32*0.4!
That's the one I was taught, and it works perfectly satisfactorily.
It does indeed, faultlessly I would say, a simple and very accurate method. However, I have some sympathy for IO540s view. If you simply assess the cross wind as being none, small, medium or big, then you simply offset by 0, 5, 10 or 15 deg and assess it from there. If you have drifted 'a lot' change heading by 10 deg, if you have drifted 'a bit' alter heading by 5 dgrees. I was taught this during my CPL not as technique for the test but as a demonstration if how simple it is to end up where you want to be without much effort. I am in no way saying this is the way a PPL student should navigate (or anybody for that matter), but from my experience the results are more than good enough.