Yes. It is a common industrial process.

Yes indeed, then it depends on what other characteristics you are interested in. (Meso)porosity for example may depend on the ph rangein which you do the synthesis.  Check also Stober's papers and books. Hope this helps, Below a general publication:

http://www.sciencedirect.com/science/article/pii/S2187076413000225

You will find a lot of good experimental procedures in literature. PH also influences the charge/structure  of the condensate. Condensation takes place in acid and basic media. 

Article Analysis of silanes and of siloxanes formation by Raman spectroscopy

The publication might also be interesting.

Article Analysis of silanes and of siloxanes formation by Raman spectroscopy

This is  a pretty good overview, pretty much bassed upomn the classic: Brinker, C.J.; Scherer, G.W. : Sol-Gel-Science, The Physics and  Chemistry of Sol-Gel-Science.

Good luck, Hope this helps :)         Per

Most likely you end up with xerogels or similar...unless you use surfactant

oh, by the way, here is the pdf-file that I referred to above :)