What I'm going to propose is not as fast.
- Before the game, assign point values to all units (say, BV2/100, round up). Multiply all units in the lower valued force by a factor which brings their total even with the higher valued force. Round any unit valued at less than a single point to tenths of a point.
- Some units may be required to declare before standard initiative begins. They do so now. If both players have such units, the players alternate as in step 4.
- At the beginning of any phase in which initiative matters, each player may designate any enemy units as "exempt" from standard initiative.
- Each player secretly records declarations for as many of his own non-exempt units (at least one, assuming he has at least one non-exempt unit) as he wants, and tallies up their point values. Both players reveal and resolve those declarations.
- The player whose tally is lowest openly declares actions until his tally exceeds his opponent's. Repeat until all non-exempt units have been declared.
- Declare actions for "exempt" units, alternating as in step 4. (Given that players will tend to "exempt" enemies they don't care about, these could be resolved quickly and simultaneously.)