paper mache glues

Hi,
I'm a painter and I'm thinking of using paper mache in a current work. I
want to give some small parts of the surface quite high and quite distinct
texture. The painting is in acrylics on canvas, and there is already quite a
bit of acrylic paint on the surface. So I want to make a paper mache that
will stick to an acrylic surface, take an acrylic paint and/or oil paint
after it dries, be reasonably hardy, stay stuck on to a vertical surface and
stand the test of time. Unfortunately, I'm a first-time paper mache user! I
have read a lot of recipes on the web, and I'm confused about a couple of
things. I'm hoping that someone might be able to clear up my confusion for
me. Here's my bunch of questions...

Why do all the recipes I have read use a mix of glues? (usually white glue
(PVA) and a starch glue (wheat paste)). Do I need to use two glues? If I do,
then what about methyl cellulose and PVA?

Do I need to worry about adding a fungicide? (Some people seem to worry
about this a lot...). If I do, would salt work?

Some people recommend adding small amounts of oil of cloves or linseed oil
to their pulp. What is this for? (I have been reluctant to add any oil
because I want to paint it, at least initially, with acrylics).

Some people add a small amount of bleach when preparing their pulp. Is this
to make the paper white? or for some other reason??

I'd appreciate hearing any thoughts you have. I'd also really appreciate
hearing whether you have tried doing somethinbg similar to what I have
described.

Thanks!

Angela