Oh goody this debate again!
There are plenty of different opinions out there especially when it comes to bolt/sniper rifles because each shot matters. Now I have heard many arguments for 6.05 being better than a 6.01. Reasons that support this one:
there is enough variation between bb brands that unless you are regularly feeding your rifle the same brand, or some super nice bb's like SGM .29's ($15 for 500 WHAT?! it's worth the price) then with a 6.01 the barrel may amplify the inconsistencies in the bb.
Here is a thread I started on arnies airsoft. They have some very experienced bolt turners there and it is worth making an account and checking it out.
http://www.arniesairsoft.co.uk/forums/index.php?showtopic=189523
In the end what ever you decided, the quality of the barrel will be the lead determining factor in accuracy. If you shell out a little more you will get a much higher quality barrel.
Edit: I'm going by Fred on arnies