Hello Rino. Looks like a great project. I haven't heard of anyone putting an W70 safety on a Sako L-series bolt but doesn't mean it can't be done!

There is a fella here in Australia that machines stocks that has an English Classic pattern to suit a variety of actions, including the L461 Sakos - the images at the link below might give you some ideas:

http://hatchersriflestocks.com.au/products-19/english-classic-sporter.html

Keep us posted on your progress,

Marcus