In reply to TheBigFactHunt:
I did both types of course last winter so might be able to help.
I did a five day Winter Skills that started from the basics then worked up. By the end we did a grade I gully and also Fiaical Ridge, unroped, probably Grade 1.5, since we didn't do the full exposure of the Grade II section but nor did we stick to the easiest path towards the end.
Later I did a two day Intro Winter Mountaineering Course where we also did the Fiaical Ridge but roped, again around 1.5. Did't do any gullys but did one steep slope out of the bowl which could possibly be regarded as Grade I terrain, not sure as I didn't measure the slope.
I guess that if the group is willing and capable in a 5 day Winter Skills course you may get as far as the mountaineering option, but bear in mind that we only had 3 students on the latter 3 days of the Winter Skills course so a lot more options were available.
I would recommend either, as both were professional and thorough, but it's pot luck how hard your group wishes to push should conditions and the instructor allow. Either way you won't be pushed too far beyond your experience, but obviously you want to be in an appropriate group and not hold them back.
Hope this helps a little.