I think a capkit is a good idea, but to be honest I wouldn't expect much... unless that monitor board is way out of adjustment (I doubt it) you're not going to get the color right just from a capkit. The geometry will probably look better, though, you should be able to adjust the picture to the right size and shape, but to me it looks like you're missing possibly TWO colors on the neckboard, or the tube is just about blown out. The red is strange, since when a tube is overdriven it usually does something like that, but your red doesn't extend to the edges of the screen, leading me to believe it's probably a problem on the pcb. The tube rejuvenator may kill the tube, as well.
I'm not trying to be discouraging! Just trying to help you fix it. Also, there is no way at all I'd pay 90 bucks for a t.v. just for the tube. Please dont' do that! If you're going to do a tube swap, just go buy a broken t.v., on a t.v. the tube is almost always still good and the board bit the dust. Save yourself some trouble though and get an older 25" t.v. if you do that, since the angle of the tube is different on the newer ones (it'll work, but looks bad).
Do a capkit, first though. I wouldn't do a flyback, they're hard to change, you might break the pcb, and it likely is working fine since you have a picture. I dont' believe a flyback would cause geometry or color problems.