Line Magnetic 219ia 12AX7 Tube Rolling

I acquired myself a LM219ia just two weeks ago. I love the amp. For the cost that I can obtain a pair of NOS 12AX7’s for, should I grab a pair and roll them now? I would grab NOS RCA’s or Mullards. Does anyone have personal experience with rolling 12AX7’s in these amps? Will the results be worth my time, and what sort of sonic characteristics or improvements might I find?  From what I have gathered, the swapping of these preamp tubes should yield the most dramatic results, followed by the 845’s. I appreciate any advice. Thank you
From what I’ve seen they (12AX7) seem to be the input tube for this Line Magnetic 219ia amp.

If you have plenty of gain on the volume, you can try different 12A*7’s.

The AX7 has the highest gain, but to me for an input tube on an amp, it’s a bit bright, good for phono stage inputs though.

The 12AU7 has the lowest gain, and will sound more mellow.

The 12AY7 is my favourite from the 12A** series, for amp input tubes, who’s gain is between the AU and AX.

Cheers George
Check with Andy at Vintage Tube Services. He will give you good advice. Give him a call, which is better than e-mail for this purpose.