I am by no means an expert. However I will try and give my opinion, I would aslo seek other opinions. First of all I think the Solartex and other tex's are great covering materials. I have always had a love/hate relationship with Monocoat that is more of a hate relationship of late.

-I would paint a light coat of white after cover. Let dry completely.
-Use HIGH QUALITY masking tape that releases easily. I use the blue stuff.
-Paint the red stripes on using light coats, just enough to cover.
-Some remove tape before paint dries, works ok if you are using latex. Fast dry sprays are a different story. Leave tape until paint is dry to avaoid a big mess!
-If you use cear coating to prevent paint creep then use a very light coat.
-I have had some success sanding the paint line with very fine wet sandpaper and then clear coating the entire airframe.
-Clear coating does help the paint line just a bit by smoothing it, but it will not elimate the paint line. I would not sand the entire painted plane.

_Build some test frames, cover and paint them to test the response of the paint you have chosen.

Hope this helps

JEB