Please do everything possible to ensure absolute tightness of the clutch drum nut and the countershaft sprocket nut. Use both the locking tabs and Loctite "Notluck" (excuse the prep. humour). No need to buy a great tool to do the sprocket nut, it can be held in a vice and the sprocket hammered around with a brass drift.
There is no excuse for butchery on bikes like ours. You can purchase the correct spanner for the sprocket nut for very little and remember, you will need it around every 10,000 miles when you replace the chain and sprockets (as a set) as part of your regular maintenance.
Here is where I obtained my spanner
http://www.ebay.com.au/itm/181301604855?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 for just A$22.
Use a length of old drive chain wrapped around the sprocket to hold it while you tighten the nut - this method places zero strain on the gearbox internals. Use a lock washer and Loctite on the drive pinion nut.
As to the clutch drum nut, I recommend that you use a lockwasher AND safety wire as well - you will need to drill through the flats on the nut to accommodate the wire.
The image shows a Honda clutch basket installed in my Comet.
I did have a Burman Clutch but cannot supply photo's as I loaned it (the Burman clutch ) to another section member and it was never returned. Sigh - that's bye bye to $400 or so and when I return my gearbox to original I will be forced to seek out a Burman unit for sale, if I can find one. Bit pissed about the whole thing but then again, by his own admission, he does have Welsh Alzheimer's.