Why are you using dye now, after you've stretched the fabric?

Usually fabric dyes are used on the bolts or pieces of cloth, before cutting and sewing. This makes it easy to dip the fabric so it soaks up the dye evenly. Some dyes need to be used hot. The fabric might be boiled in the dye vat, or it might require ironing to 'set' the dye.
You are way past the point to properly use most fabric dyes--so why do it?
At this point you might think of using a tinted urethane or polyurethane varnish. Or maybe a coat of thinned paint.

It is time to seal the fabric and waterproof it so you can paddle the boat. There are many tinted finishes available, or you can buy a clear finish and add a few drops of colorant and tint it yourself.

Go light. Adding coats of your waterproofing material will deepen the color. When it looks good, finish with a coat of clear.

Just a thought

PGJ