the problem with water effects is that it will end out translucent, I find that will probably look rather unrealistic for lava. lava is normally opaque. It will look better IMHO to just use red paint
Your lava looks very nice by the way. I think you can give the lava a more 3 D effect with water effects by adding a thin layer of water effects between some of the layers as you paint it. A very tiny amount of glitter can be used to give the spark effect. Try neon yellow. I saw this done with an Ice flow river river section. The ice blocks were painted between the clear layers and it looked like the ice was floating in the water. You could do the same with lava.
I have not done a lava board. Sadly I did not take a photo of the river section it would have won awards hands down.
I am suggesting that you make a pool like I did for this 40k section. Use yellow as the base coat and paint the lava on top of it. The light will reflect from under side and will make a cool effect. I made the bubble effect with glass beads.
I used the still water for these wells. You should be able to paint the darker lava colors on top of the still water.
you could also imbed stones in resin to give the impressions they were floating on the lava. Just use lava colors instead of earth tones.