Thank you so much Matt, that is a great help. I'll be ordering some PVA tomorrow.
My usual burnishing reportoir is to rub the dyed edge with beeswax, then use my burnishing machine to do the hard work, occasionally using an edge slicker for the awkward bits. I've found that a beeswax coating, coupled with proper burnishing gives a nice result for my needs, finished with a brisk rubbing from an old pair of denim jeans.
I used to dye, then use gum trag, then burnish, then beeswax, then a second burnish but discovered one day that the end result was the same as if I'd just used dye and beeswax, burnishing just the once, so I skipped out the gum trag part. I do still use it occasionally if I need to smooth out a detailed flesh side, but that doesn't happen too often.
I'm guessing that the PVA does the same thing as the gum trag, as in keeping the fibres tight? The fact that the PVA and dye powder are mixed together would mean that it's an all in one solution?
Thanks again for your time and advice, as I mentioned I've not used powder dye before so I'm a complete novice in that sense.
Spud.