Hi Whynot. Paint instead of ballast sounds a bit off the wall to me. Leaving ballasting until after an extensive test in case you need to change a point or remodel a bit of track is a very good plan - but leaving out ballast would be odd.
I know at this stage ballasting may be like contemplating an act of vandalism on your new track - but it makes a huge difference visually. It doesn't require any physical dexterity and isn't demanding on eyesight.
If you do a test piece on a foot of leftover flexi track pinned or glued to a piece of offcut timber frame material you can try it. There are lots of videos showing how people have done it so you can get the notion. The time honoured method of dripping a PVA/water/drop of washing up liquid on it to seal it down works well.
My own experience and reading the rare cockup stories on forums suggest :-
1. Do it in 6" sections and don't stick your finger in it the next morning.
2. Pre-wet each section with a fine spray mister.
3. Use an eye dropper to drip the mixture on. Syringes are useless - pressure builds up and blasts the ballast off the track.
4. Leave the ballast out of the point operating bar area.
5. Utterly ignore glue spraying suggestions - there is such a device on the market.
You will also see posts on forums saying " ballasted the entire layout layout last evening after work". Smile as you read it. It takes about a week in small sections to do a layout your size.
But try a test piece as mentioned above.