This is the suggested power up sequence at the beginning of the game:
Speed Up x2 - Missile - Option x3 - Barrier - Option - Laser
First of all, two level of Speed Up is the basic requirement in most places. Next is Missile and then Option. In some positions, like near the end of Bubble stage, the need of Option is essential than Missile - Option is sometimes equipped before the Missile. The last equipments should be Barrier and Laser, because they're not much necessary in the first two stages.
This is important to notice that Option Hunters appear in this title are of very troublesome. The apparence of an Option Hunter can result in highly dangerous situation if without preparation. This is exactly the reason why is "Option x3 - Barrier - Option" instead of "Option x4". If you equip the last (4th) Option near the end of Sky Battle (power up zone) in the beginning of 2nd stage, Option Hunter will then appear in the joining section near the middle of stage 4 where it will be all save for you to decide either escape from it or let it to steal one Option from you. The position at where you equip the 4th Option will directly affect the appearence time of Option Hunter. And in the 2nd loop, it count on the 1st Option.
If you didn't equip the 4th Option(use only 3 Options all the way), Option Hunter will not appear. But it seems there is no necessary to do so. By the way, the counting time of Option Hunter will be cleared if you crashed a plane.
Power Up Sequence