Who are best old violin estimators and where they are located ?

[Alexionov]

Gentlemen,
 
Please help me somehow. I have an old antique violin, possibly 250-300 years old. Possibly Tononi's (not sure) slim chances that it is Stradivarius (not the same stamp). Back stamp is a flower-like and it is on two places. Both are in axes with the violin's neck. First one is next to it (top of the upper bout) and second down at the bottom of the (lower bout).
I would like to know where I can find more information about best estimators for these instruments (location, telephone, website if they have)? There are lots of frauds out there and I really don't want to waste my time with them.
 
Thank you for helping me.
Alexionov

[BassClef]

Upload sme good quality images to photobucket and put s link to the photos here. The will better help the experts evaluate what you should do. Front, back, scroll, sides, bottom, etc. Also, where is the violin located?

[Blank face]

 

Back stamp is a flower-like and it is on two places. Both are in axes with the violin's neck. First one is next to it (top of the upper bout) and second down at the bottom of the (lower bout).

 

Don't want to disappoint you, but this sounds like typical marks from a ca. 1900 Schönbach industrial produced instrument, no Strad nor Tononi.

Do they look similar to this:http://www.maestronet.com/forum/index.php?/topic/331286-anyone-know-this-violin-brand/?hl=brands?