P.S. I would not use English tech grades (unless revenge through confusion is the objective) peak bouldering grades are my favourite (i.e. B grades). They cover the low grades pretty well.
But B grades are just SOOooo 1990s darling, and English tech grades positively retro...
More seriously it appears in the UK from what I read V grades are becoming dominant. Rockfax is using them in all its bouldering guides, as has Simon Panton in his N Wales new boulder guide. Dave Mcleod is writing a bouldering guide to Scotland for the SMC (will wonders ever cease? The SMC boulders!?!), it will be interesting to see if he uses V or Fb. Perhaps we should get the Finns who now seem to be resident under the Keel at Almscliff to come back over and regrade everything in V grades!
I've never really got Finnish bouldering grades, I was told originally that it is a full grade lower than a route grade, but for example some of the 4s at Vessolandet didn't feel much different from 4 or 4+ moves on routes, and the 5-s at Viirilä (probs 1 and 2) can't have been any harder than 5- or 5 on a route. Then again one of the sit start problems given 5 at Viirila I couldn't really get off the ground on! (Fat arse probably to blame there...)
I remember a problem at Taivaskallio which is 5- which took me maybe 5 or 6 goes to get.
Of course some problems are your 'style' (for me crimpy/slabby) and others not (overhanging/slopers), but still there seems to be a fair amount of variation around.