I use to use dullcote and their semigloss but I always airbrush it. This gives you much more control. You control the shine with the way you spray. They spray well but both rub off if handled too much. I think Tamiya's Flat(TS-80) and Semi-Gloss(TS-79) spray better out of the can and are much more durable.
Try soaking in water overnight. water will eventually soften and weaken it. Do not use suprglue for windows, you are asking for trouble. Try a good PVA glue like Formula 560 Canopy Glue or Microscale Krystal Klear. It can be rubbed right off or wiped off with water on a Q-Tip. It does take awhile to setup but the safety factor is worth it. It holds very well when dry.
This one was finished about 2 months ago but I just now took some pictures. The work in progress is here http://www.modelcarsmag.com/forums/topic/100895-mclaren-f1-gtr-update-decals-51915/#comment-1410302
It is a great kit but beware anybody buying Tamiya kits from this time period(early to mid nineties) Tamiya had issues with cracking decals. I would not buy these kits unless I could see the decals in person.