I've not used any of the new
GW washes - the old ones didn't give a shine though I have heard some of the new ones do. Ask in store, or here on the forums and I am sure someone will be able to tell you which ones leave a gloss finish.
Watering washes gives a much weaker shading effect which can be very useful. Painting things white then using a weak wash of black, brown or blue helps with shadowing the white with little effort and also can help to give it an interesting hue.
Again, I have not used any of the new
GW washes and I don't water down my inks (which dry with a gloss finish) as I want a nice solid colour whenever I have used them, however, I would imagine if your washes dry shiny then they will dry shiny if you water them down, though as with the colour this will be less intense.
For contrasting/warning colours you can never go wrong with yellow and orange, though they can be a pita to paint sometimes.
I think your
IG would look good with either blue, red or green goggles and maybe some small orange unit markings (even edging your current unit markings with an orange line) would really just break up the grey.
Basing is really easy - for minimal effort you can get something looking pretty cool.
The base for this guy was done using "fine" basing material from Gale Force 9 for the main ground cover, a few blobs of PVA to hold tufts of GF9 static grass and some GF9 large basing material to make the little rocks. Other details include the ribcage and the little musroom made from greenstuff:
Basic troops have the same kind of basing, though more generic with fine basing material and static grass and the odd larger bit of basing material:
The rims were then all painted brown to match the table.
Each base takes about 5-10 minutes to do in total (without drying time) and you can easily use sand and stones instead of "actual" basing materials.