Raid :
You get one battle no matter how much clones you send. Your aim is to bleed clones if you want to take the district or to have a nice game if you just want to fight.
The attackers can setup the timer he want. However, if the defending corporation is unable to provide defense (attack at 18 on a US district as an exemple). Then the attacker win NOTHING as there is no ISK for biomass, no salvage and no clone losses.
For it to be a viable mean for attack, a successful raid would result in the loss of as much of clones as the defender put in the battle, the attacker would be able to launch another fight against the district and no regeneration would be given for one day.
ItGÇÖs up to the leader of the defender team to decide if he can kick the attacker here, or if it is better to keep clones for another battle.

Salvage :
Like for the raid, you get only one battle, the timer is also set by the attacker. However, there is no re-up possible and the defenders still get a regeneration no matter what is the outcome.
The objective here is to kill clones to make money, it would provide a bonus to salvage and ISK reward, based on the gear. APEX and BPO donGÇÖt provide any reward though. Both sides can salvage, but only the winner get the ISK. The ISK pool is calculated on the gear lost by BOTH the attacker and defender.

Attack :
The current mod. You fight to get the district. As much battles as the attacker have clones and victory screens. However, you can fight only on the timer set by the defending corporation (the timer part is bellow)

Cargo Hub 450 clones - 80 regen
Production Facility 300 clones - 100 regen
Lab 300 clones - 80 regen :
Command center 600 clones - 80 regen (1 per corporation)
Factory 300 clones - 80 regen

There is a bit polemic on it between CCP that want fixed timers, and the corporations that want to put timers when they want.
I donGÇÖt know if you can, but I think the best would be to calculate a set of timer per corporations based on hours of activity.
If I take something I know like my own corporation, I know that most of my guys will be more or less available between 18H and 22H Eve time. Except for some people who can play all over the day, it is the average time where IGÇÖm almost sure to get 16 players (provided they arenGÇÖt all eating ).
Or at least, add an option in corp managment/corp warbarge that allow directors to set a specific time zone (EU, US, AS). Depending on the timer selected, the corporation get a defined set of timers :
EU : 18 - 21 - 00
US : 22 - 01 - 04
AS : 10 - 13 - 16 (I donGÇÖt know the best timers, but I apply the same logic than for the others basing myself on the very popular 13h timer)

This would delete the unreachable timers between 05 and 09. A good start.

Fixed timers is the worst idea you ever had (and I was a pilot before 1.7). One day or later, youGÇÖll regret it.
You are currently justifying this by telling to corps to expend and have players in every time zone while in the meantime you want smaller corps to be introduced to PC.
IsnGÇÖt it a lack of logic ? Experienced players donGÇÖt grow on trees, especially on DustGǪ (except if you are building a secret clone army on Kamino of course)