Thank you very much tillystuff.
Your info as well as the URL were very useful to me. I hope I will get a fairly decent mount next time and it will definitely NOT be on redwood
winterwhite: I used redwood because I had them in my possesion. It is used in aquariums since they will not float when dried. But from the texture of the wood I am almost sure it is not a good choice. Besides it is is so hard that one will break a few drill bits and one should be ready for some 'smoke' to come out too.Another thing to consider is the price. In Canada it is sold by Lb/Kg and the price is prohibitive
As per tillystuff's suggestion grapewood and cork bark are the choicest, as far as I have read so far.
tom499: A very good effort. Keep it up. It seems like a softwood to me. May be some one else can add more on its longevity as a mounting medium.