Highest I'd go would be a Medium BA as the proverbial assault suit.
Mostly Ballistic and Missile, if any Energy it would be Chemical at best.
This is for an AU timeline, circa 2890 - current, 3149.
Armor, Speed and Armored Gloves, using projectiles.
Mostly Planetside and a few Space adaptions.
Fluff based of the Nighthawk XXI and the rarer XXII, kinda like the P12 Tornado but no special equipment other than primitive tech. Like stripping the armor for basic plate, UMU / Space Adaptions.
Unit in question could have torso mounted weapons, assume Clan base, but built as IS Standard.
Idea is I have some in a detachment of SOG deployed with a Royal unit get caught in a misjump, leading them to replace their functional armor for stripped down suits using local materials. Enough suits to accommodate the needs of a four realm "sphere".
Thank you for reading,
Loremaster Truetanker
Clan Iron Dolphin (3152)