Congratulations on your new motorhome. We bought a 1994 Brave last year. One really big advantage to buying a Winnebago is that it is really easy to get information on the older models. Here is your brochure which will give you the specs. on the tanks along with other useful information.
I'm not sure what model number you have but there is a document available for your RV similar to the one below that will give you a detailed parts list so when you need to find something you will know the part number and can order it.
Unfortunately the above is not for the vectra since I don't know the right code to enter to get it. I believe it is for the Chieftain based on the info. in the Owners Manual section of the document. If you look at the sticker near the driver's side door area you should be able to find your model number and then substitute a combination into the last section of the above link and pull up the parts list. I can't figure out how to navigate to these documents directly so use trial and error with the model number to pull up the right parts list.
To show how to do it for the chieftan the model number is 1994 WCN34RQ. So to get the parts list you enter the last two numbers of the year, use the WN from the letter code but not the C and then the 34 RQ (34 ft, rear queen).
For example mine is a 1994 WCF29RQ.
The link for my parts manual is http://www.winnebagoind.com/service/...94/94f29rq.pdf
In my case you do the last two numbers of the year, the F (from the letter set) and the 29RQ.
A third example is for a 1995 Itasca Suncruiser. The parts list is: http://www.winnebagoind.com/service/...5/95ig34ra.pdf
The model number is 1995 ICG34RA.
You can see that you again enter the last two digits of the year, then the IG from the letter code (dropping the C) and the 34 RA (34 ft. RA for the side facing bed).
Basically a little trial and error with the letter code should get you to the right document. I saved mine to my hard drive in addition to the link, just in case the link should move in the future.
If you can't find your parts document post the model number and I'll see if I can locate it.