Good day Shonit123,
In all my years in the Infantry I think I can say that there is no set standard for what went on a helmet in the way of scrim. The Woodland helmet cover had two rows of slits around the circumference of the helmet for sticking foliage in, along with under the elastic helmet band. This was not conducive to scrim, so enterprising soldiers used various netting over the helmet cover to which they then could apply all manner of material.
I myself have used the earlier netting (cotton cord knitted into netting with about 8 to 10 cm squares). I have also used cut up pieces of the newer vehicle cam net (nylon thread braided into a net with squares about 40 to 50 cm and coated with vinyl to which was fused vinyl sheeting that was OD on one side and black on the other and cut in random semi-circles to create a multicolour surface on either side). To the criss-cross threads of either type of netting was tied various strips of burlap as mentioned above. We usually used the tan hessian available from CQ stores cut into strips, or cut-up sandbags. I believe the multicoloured hessian strips were reserved for the Recce Platoon's Snipers. i have also used cut up combat scarf and even an old CF Green scarf.
However, I have never heard of someone using Garrison jacket material. That's not to say it was never done...I'm just saying I've never heard of it.
The end result was to avoid "Why Things Are Seen". All you Combat Arms types repeat after me -- SHAPE, SHINE, SILHOUETTE, SIZE, SPACING, MOVEMENT, CONTRAST, COLOUR (there may be one or two I've forgotten, feel free to correct me. LOL!!)
So, I guess what I'm trying to say is that you won't be wrong, as long you don't go overboard....don't have you helmet look like a wig with bits of scrim covering every inch of the helmet. Send a pic of the finished product so we can comment, please. Best of luck.