I did my infantry set up by tech level. So Tech B infantry get tech B equipment to pick from, Tech C infantry use tech C equipment, ect. It makes for some interesting design decisions, and the unit combinations that resulted feel like something that would exist organically, not something that is min-maxed to exploit the terrible infantry construction rules.
Like, the grunts/militia/police/civilian partisans get tech B stuff, so they get bolt action rifles, and use mortars or bolt action snipers.
Core military infantry at tech C get grenade launchers/SRMs, and the autorifles/machine guns
Tech D starts getting into fancy armors like Ballistic Plate, laser/blazer/pulse laser rifles, anti material sniper rifles, and for support the laser/heavy laser support guns, AA weapons, and LRM/MRM launchers. Elite or Special forces type stuff, too expensive for traditional infantry. Like, yeah the Marians have their great damage divisor 2 armor, but with its price tag only techD rated troops have access to it, not every grunt in the Marian armed forces.
Tech E is the Mausers and really high end stuff, too expensive for line infantry but good for showcase units when you want to throw cash around and show off. Like if its 3075+ and you want your bodyguard team to have the most expensive gun that exists, you get a Mauser 1200. Since such showoff Royal Guards/cyborgs and such have a reason to exist in battletech, having a single Tech E platoon or squad, perhaps with full cybernetics, makes sense as a 1 of unit that exists in theory but doesnt really show up in a line battle unless some super VIP in a limo is getting attacked as part of a narrative story.
