For upgrades, i suggest playing it safe with 2 upgrades on attack and leave it as that. Any more and it will not be cost efficient, since they already cost 1k vanilla. Speed is very nice in FOTS but not worth the upgrade on shogitai imo.
As for your loose formation question. If you have the micro for it, leave them in loose when charging and just as they get near the enemy, reform into tight formation. Loose formation is for reducing casualties when taking missile fires, tight is for malee combat.
hope what I said makes some sense and helped