Jump up in tempo or just write in faster note values?

I have finally, 4 years after the conception of my first symphony, started writing it out in Late November of this year. So it's been roughly a month that I have been working on this symphony. But it's been on and off with weeks between me writing the first part of the canon in the Introduction and the rest of it and then several days between me finishing the canon and starting the Allegro alla Marcia. This symphony has a battle narrative to it.

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A march in the first movement Allegro, a fast march, with a tumoltuous development section where the major key "Hero" theme and the minor key "Enemy" theme are literally battling for the spotlight and in the process of said intermingling, breaking down, followed by what seems to be a victorious recapitulation for the "Hero", only to be thwarted with minor in the Coda before finally cadencing in major.

Then a funereal second movement with intermittent brightness of major in memory of how hard the troops fought only to be emotionally swallowed up by minor again in grief of those who have died, and fragmentation in the final minor key section as if it's hard to speak in all this grief.

Then a Scherzo, but not your ordinary Scherzo. No, it's a Double Scherzo and Trio, so the Scherzo section shows up 3 times, in its heroic mood and the Trio section first shows up in minor as though the "Enemy" is still strong and then a second time in major as the "Hero" approaches victory, for real this time.

The Finale is victorious and triumphant. Minor is no longer with us, it's all in major. A different brass fanfare shows up in this movement than in the first and third movements to further emphasize this victory over the minor key that was truly threatening in the first movement. Not sure if I should end this movement quietly or if I should have a quiet start to the Coda followed by a blazing fortissimo ending cadence. I know I want that quiet section of solemn gratitude towards the end of this movement though.

I am currently at the first theme of the exposition, the "Hero" theme, which I divided into 3 sections. First, at Bar 27 is a quiet part starting with solo flute melody over a march rhythm in the timpani and lower strings and gradually building up in orchestral texture until the crescendo in Bar 42 that leads into the brass fanfare at Bar 45, where the trumpets enter for the first time in the symphony. After this fanfare, I am wanting a full orchestral version of the march and I'm also wanting it to feel faster as though the "Hero" is charging into battle. I feel somewhere between 140 and 160 BPM is a good tempo for the full orchestral march. That is, if I go with the tempo jump. I could also just shorten the note values, so instead of being eighth note dominant as it was in Bars 27-44, it would be maybe sixteenth note dominant? I'm not sure which to go with. I mean, going with the note value option would make it easier on the conductor's part. But with the tempo jump, I could get it to precisely the speed I want and not be limited by the note values to certain speeds.

So, what do you think I should do to give this full orchestral march a feeling of being faster as the "Hero" charges into battle? Should I just use more sixteenth notes in the melody this second time through with the march before the C minor of the second "Enemy" theme comes in and the notes slow down? Or should I have the tempo jump up, so that it goes from eighth notes at quarter=120 to eighth notes at quarter=140-160(somewhere in that range)? Here's what I have so far of my symphony: