Spearhead is indeed nothing like MP, it's … more concerned with command decisions rather than how many millimetres of armour plate.
I understand this.
This is one of the reasons I prefaced my comments with the caveat that I could offer no insight into how to implement my particular approach within the rules. I might not have been clear in my posting, but I tried to focus on the issues that might define a commander's tactical approach, leaving it to those who know the rules to figure out how they might implement their intent on the gametable.
Perhaps the Spearhead rules pay no regard for MG fire on infantry. If so, I expect I'd read a lot of gamers suggesting the rules were a waste of time. But I don't. So I infer (perhaps incorrectly) that MG fire has some effect on infantry.
And perhaps the Spearhead rules pay no regard to armored protection from small arms fire. Again, I expect I'd read more objections to the rules than I do.
Now please note, I am not discussing or describing millimeters of armor, or millimeters of penetration, or any such thing. Whatever the rules provide as mechanics, does armor provide some protection from small arms fire? If it does, we have lift-off.
The key to success of tanks like the Pz I, in MY observation, derives from the ability to use their mobility and protection levels to concentrate overwhelming MG fire against infantry formations that don't have ranged AT weapons. I observe this in my readings of early war history, and in my own gaming (with different rules, as I freely admit). In actual fact the infantry's morale often failed. But there was a reason for that -- they could not withstand the MG fire, and they could not dissuade the tanks with small arms.
The OP was framed in terms of early war. As an example, a French infantry regiment in 1940 would have had, at the battalion level 12 platoons of infantry, and one platoon of 2 25mm AT guns. At the regiment level there were another 6 25mm AT guns, which operated as two 3 gun platoons.
We are speaking of a distributed density of no more than 1 gun per 6 infantry platoons at the battalion level. Given the paltry effective range of the French 25mm gun (about 600m IIRC) and even with ATG reinforcements from Regiment (not highly likely), the likelyhood should be that no more than 1 out of 3 or 4 infantry platoons have ANY ATGs within range to provide support.
In this case the challenge for productive use of Pz Is is easily met. Bring 2 platoons of Pz Is into position to concentrate their fire into one platoon of infantry. If there are AT guns in range, move off and find a different infantry platoon to pick on. Don't close with the infantry until you've reduced them to ineffectiveness. Whether that ineffectiveness is due to casualties, accumulated shock value, disorganization, reduced morale level, suppression, or any other rule mechanism doesn't matter to the case at hand.
If the Spearhead rules are structured such that that a platoon of ~35 men can withstand the concentrated fire of 20 MGs, or that small arms fire alone can dissuade armored vehicles from firing their guns, then find a different set of rules, because either of those failings makes the rules useless for gaming combined arms combat.
And please note I am NOT criticizing the Spearhead rules. I presume this tactic will work, as I have read so many positive reviews of these rules. I can't tell you how to move or play your pieces to effect this tactic, but if you can figure that out, I expect you will find it works.
Again, your mileage may vary.
-Mark
(aka: Mk 1)