Lets see if I can answer some of your questions.

5/2 Valves go much bigger than 1/4 ..... 3/4 is the biggest Ive seen.

Have a browse thru this online store...http://www.airlines-pneumatics.com/webcat/product-index.asphttp://www.airlines-pneumatics.com/w...duct-index.asp

The fitting I think youll need for the rubber pipe from the compressor is a hose tail .........cut the pipe ,push the fitting inside and use a jubilee clip or similar to retain it.

Youll find them here:-
http://www.airlines-pneumatics.com/webcat/vit.asp?SubCat=3http://www.airlines-pneumatics.com/w...t.asp?SubCat=3

Educational site .... http://www.teamdavinci.com/understanding_pneumatics.htmhttp://www.teamdavinci.com/understanding_pneumatics.htm

Note also that pneumatic thread sizes are weird ...see if my page on threads helps.

http://www.teamonslaught.fsnet.co.uk/threads.htmhttp://www.teamonslaught.fsnet.co.uk/threads.htm

Woody