Since LOS & range are determined based on the units, & not the individual elements that comprise the unit, the easiest thing that all players should be doing is doing focus fire. Pick 1 element in your opponent's unit, based on whatever criteria you want (least amount of armor, lowest/highest TMM, highest damage it inflicts, etc.), & each turn you focus-fire on that element in the enemy unit until a) your unit is toast or b) you turn the target into charcoal.
BF makes it simpler. Instead of having to count every single hex the target moved to get its TMM, the TMM is fixed. Take a look at the enemy Unit Record Sheets before gameplay starts, & either have some blank index cards or Post-It notes available, & jot down the quick information you need (MV, S/M/L/E damage, Armor/Structure), & then you don't have to keep looking at the sheet. That works if you only have 2 players. If you have multiple players (with each player controlling an entire Unit), you're probably going to have to keep looking at the sheet each turn, just to see what other fire effects may have occurred, but that's no different than what happens in CBT. And if it starts getting too long, you can always implement "one-minute" or "two-minute" rules for declaring attacks. But I would definitely lean more towards the "do a little extra prep work before the game", as it will save a lot more time during the actual game. Heck, you could even make a house rule that everyone has to make two copies of their Unit Record Sheets: one that they use to track, & one that they give to the other side's player(s) as a reference point (whether they want to also track it is up to them, but then they at least can quickly look and see what TMM your units have, & vice versa), without having to always hand your sheet over).