I wouldn't use 8/6/4 though, this seems the worst combination of variants that is possible. some templates I would use:
Quite high Soft Attack for quite a low cost of under 5k IC. Remember that you can even convert old LARM1 into LSPART2 and old LARM2 into LSPART3, which works very well with conquered Czech and French Tanks. The fuel usage with 17.2 is also quite low. Of course the armour is minisucle, enough the defend against pure infantry, but support AA1 will pierce. Still very decent against AI.
This is why you can put in 1941 MARM into the division, you lose a bit of org and speed but still a very fine with over 10 km/h and over 35org. Fuel usage goes also up a bit, but still qzute low. Production cost is over 5k now.
But you can 36 armour which helps against AA2 piercing, your soft attack goes up a bit more, you get good piercing against enemy tanks, and with 193 breaktrough you should be quite save against enemy infantry damage. Your hardness is also quite decent.
compare that to a somewhat regular tank division, 9k IC cost and 47.5 fuel usage, this will cost you alot. 780 breaktrough is far more than enemy infantry can bring soft attack, so a bit wasted there. You get quite nice hardness and a combination of soft and hard attack, making this division ok against other tanks and infantry alike.
If you go 15MARM/5Mot or even 5 Mech you can even more attack but of course your IC cost goes up even more.
Now if you use pure MSPART instead of pure LSPART you get a somewhat higher soft attack, but also a bit higher IC cost. this scales roughly linearly. But Light Spart you can produce much earlier and and convert older LARM you capture. You get more armour but with under 30 armour, AA2 can still pierce you.
If you mix MSPART with MARM you get again decent breaktrough, but you soft attack values are only slightly higher than LSPART+MARM. Again for LSPART you can get an easy stockpile early and convert older stuff. I would only use MSPART when you have researched the Panther and can convert old Panzer IV MARM2 into MSPART3 in best case replace MARM with Modern Tanks.