changing tubes on a TM18 head

Hello from Greece!
My name is George and I am thinking of buying a used TM18 head, and I am glad I found this forum!   
Now, concerning the TM18, one thing that comes to my mind is that I am probably going to change the tubes. As far as I've seen from the pictures the first thing that you can read on the tubes themselves is "CHINA". Which I don't like at all.
On my Mesa Boogie Studio 22+ I used only Mesa tubes that seemed to sound better that any other brand I tried there.
On my Seymour Duncan 8440 tube, I am happy with the Sovtek ones.
Any advice on which tube brand would fit better with the TM18? Mind That I mostly play Hard Rock and power Blues and I use Humbuckers (PRS McCarty). Let's say, Gary Moore's sound would be my favorite.
On the other hand... any experience on military tubes? They're everywhere on eBay.
Thanks in advance,
George

Hi George! I had a TM18 head for a couple years before upgrading it to a GM36 just recently.

I immediately changed the TM's tubes to JJ, mostly out of habit (it's what I tend to do with most amps I've owned) and I kept the stock tubes as spares. IMO the stock tubes didn't sound bad, but the JJ's are a known entity to me and I have a high comfort level with them. I did notice a slight improvement with the JJ's, a smoother tone, but of course that is subjective and I will emphasize it was a subtle difference.

I plan on doing the same with my GM very soon, I'm waiting on a quad of EL84's as we speak

Good luck!
-Dave

thank you very much Dave for the reply! Good luck to you too on the GM36