Impossible Timetables (Really Long and probably useless)

[psion_x]

No: HPFGUIDX 35594

I know this has been addressed before but I was wondering if anyone 
had actually managed to figure out the answer.
We know that Madam Sprout and Professor Snape have combined classes, 
and using evidence from the books it seems that for the First two 
years at Hogwarts one has three lessons a week from the main 
subjects ie: Charms, DADA, Transfiguration, Herbology, History of 
Magic and Potions, and from then on two lessons a week for all other 
years. 
In Sprout and Snape's case this has them with a workload of 32 
periods per week, a bit much maybe but I've always assumed the 
higher year level the more periods you have until in 7th year you 
have 7 periods a day which is normal in some schools.
However, all evidence points to Charms, DADA, HOM and 
Transfiguration been taken by each House seperately. This is where 
the biggest problem lies, under the above system, three classes a 
week for 1st and 2nd years and two lessons a week thereafter 
McGonagall, Binns, Flitwick and Quirell/Lockhart/Lupin/Moody would 
have to teach 64 lessons a week!
I assume once OWL's are over new subjects are taken but I've always 
assumed that Charms, Potions, DADA and Tranfiguration would remain 
compulary because of their importance. In this case how do 
McGonagall, Flictwick and whoever's doing DADA do it?
Evidence so far suggests that there's only one DADA teacher and so 
we can assume this for others to.
Is this yet another unsolvable problem that JKR has inadvertly 
written? Or are there really other Charms, etc teachers unlike 
though this seems (Fred and George are taught by "Moody" in Sixth 
Year after all).
Unfortunately for me, I can hardly wait for the next three books to 
come out since I'm writing a fan-fic at the moment that focuses a 
lot on classes at Hogwarts and what they involve etc.
So the question is do I just let the Teachers 'worry' about it, or 
introduce new ones?
Alternatively if Charms etc classes were sometimes broken up into a 
two house per class basis (say one lesson a week) this could bring 
the teachers workload to 40 periods a week, though there's no 
evidence of this in the books (maybe the Ravenclaws in Harry's year 
are really boring or something?)
Unfortunately for me again, my fic is not set in Harry's year and 
I've always believed that Harry's year is a very very small one due 
to the fact there would have been many deaths in 1980 particularly 
of babies (Voldermort was out to kill Harry remember). In other 
words the year I'm writing about has about 30 or more students per 
HOUSE year so combining two of them together would leave a class of 
60.
So you can see my problem.
If anyone could offer some good suggestions in regards to this 
problem it would be greatly apperciated.