You don't HAVE to place it in a diamond. I've done both and alternate just to give my skin a change. It really makes no difference in my opinion. Try both and see what you prefer.
Yes, Hollister wafers have measurement guides that you can cut to fit. They come with a measurement guide. Measre yourself and if you're between sizes, place the guide over the wafer and trace before you cut.
Re: your mismatched bags - If the plastic ring on the bag snaps into the ring on the wafer - you've got a match. I use NEW IMAGE as well. They are very sturdy and work well. I always use a barrier ring underneath. I've used Hollister rings and currently use Eacon rings.
I'm actually scared to try the moldable Convatec wafers (have some samples)!!!
If you're nervous about
trying something new, do it on a day that you'll be at home so that if you hate it or have problems you won't be out and about
Hope that helps.
29 yr. old female - former chrone's/colitis patient (8 years).
proud owner of a brand new ileostomy (5 months).
disease free and enjoying it.