I've done a few things for Vinyl - with little to no knowledge about mastering for vinyl.
Once a normal CD-master got pressed and it turned out okay - not perfect. Ever since I leave a few db's of headroom as the audio gets mastered again in the press-factory. I DO compress etc. like I would for CD, I just don't turn it louder.
Yeah you can get away with putting a limiter/compressor on the master fader just to catch the peaks from hitting over 0 db.
I usually leave the threshold at 0 db if I even use one at all.
(there's little sense in applying a crappy L2 or the like when the vinyl cutting engineer has big warm boutique compressor/limiters and eqs)
If you try to make it louder yourself its more than likely going to come out like a "bag of smashed assholes"
Also vinyl carries bass freq. very well. I would try to give the mastering engineer a "flat" version of the mix and let the mastering engineer do his thing.
And also due to the fact that other genres of music that use vinyl for their main medium(dance music)...their pressings come out much louder and cleaner than any other genres.
For some reason (for the most part) metal, rock, hiphop ect... come out like crap (either low,bass heavy,or smashed and distorted).Even from major labels and bigger artist.
Hopefully this french label is going to one of the better cutting houses for the vinyl master. There's a few places I would highly recommend.
http://www.exchangemastering.co.uk/ - ask for Simon
http://www.masterpiece.net/ - ask for Beau Thomas
These guy are amazing at what they do with vinyl. They might not be known for handling the metal but, that's really not the point here. They handle the vinly
J.
J.