For myriad reasons I mostly now play "student" quality instruments ... and enjoy the heck out of them. Too, as I demonstrate to beginning students I tutor, I feel it would be unfair to utilize a professional instrument to do this.
Getzens are renown for their valve quality, and yet mis-alignment occurs to them as well with extended usage. From time to time I play a Getzen Capri when I've not loaned it out to a high school band student while theirs is being serviced. Too, it was a Getzen I rented while minoring in instrumental music in college.
I may not be a pro, but I play an instrument also favored by Gmonady ... an Olds Ambassador (no longer manufactured). While mine may not look like Gmonady's, since he's had his luxuristly restored, I won't say mine plays less well.
Yes, I've played and recorded the DOD version of The Star Spangled Banner, our National anthem, and also Sousa's The Stars and Stripes, Forever!, our National march, and played all parts of these on different brass instruments, and dubbed them together (the parts, each song separately).
My recommendation is go for having the 300 lacquer stripped, but specify that new lacquer be epoxy. Too, while you can, have the valves aligned. As others have said, it may be a waste to acquire an ugraded quality instrument, that if purchased pre-owned by another would also have much the same problems you now recognize. The only concept that justifies getting a professional quality instrument is your child's pursuit of a music major in college and professional performance following, the latter if only part time. The 4 12 year olds I'm tutoring now, recently performed a 4 part rendition of O Little Town of Bethlehem at the Christmas caroling here.