inner valve spring length.

hi, the xj has now done 110k miles. 75k miles by me in the last two years so am giving her a rest and a few new bits. i was amazad by how little wear there was in the engine, pistons are fine. barrels are fine, but the rings are worn, as is right and proper. however having stripped and measured and inspected i have a problem. -
does anyone know what the length of the inner valve spring should be? the haynes workshop manual gives a length of 35.9mm. i have measured all mine and they are all within 0.05mm of 35.6mm, it is very unlikely that they have all compressed to the same size so exactly, so is the haynes wrong?
another possibility is that i have the wrong springs. they are a discontinued item from yamaha so has someone put the closest he could find in?
the outer spring lengths are good so i am realy not inclined to believe this is compression of the springs but one of the two possibilities above. all that said the springs didnt have a detrimental effect on the engine, it regularly showed speeds on the speedo of twice the national limit here in the uk, but only on private roads of course. any help greatly appreciated.
as a final note at the time of taking it off the road it was still running the twin tdi set up i put in when i blew tthe tdi unit, all detailed in a previous thread