blackknight, email me what you want and ill explain the trig formula - its useful to know it cause it also helps doing polar stereographic calculations (that is what theyre called isnt it?) if like me you hate doing scale drawings!
for now though, i would suggest getting a handheld gps and noting down drift and g/s when you are flying and looking at it afterwards if you have time - its very handy to be able to estimate such stuff at short notice for diversions and so on...