FB,
That’s quite an unusual way of bombing, if you’ll accept some constructive criticism?
My first two suggestions would be to get rid of the pilot’s door, and to leave the crewman on the ground to look after it and get your refreshments ready for when you refuel
The crewie is 90-100kg of talking ballast, and with the door off the pilot can forget looking at a tail mounted camera and minimise glances at the mirror. If you can drop the co-pilot then that's another ~100kg that can be translated into water in the bucket: both together would add a couple of hundred litres.
We all use long line with buckets, generally 50’ to 100’ (20 or 40 metres, roughly) to give good tail clearance plus allow pickups through trees etc, and don’t need another hand to release the water at the right point. With a very little practice you’ll be quite adept at getting the bucket into the pickup point ahead of the helicopter (bit of a flare) and fill whilst flying over the top, then pull the bucket out as you depart. 8 seconds should be all you need.
Finally the difference between 500lt and 1,500lt can make all the difference between controlling a fire and simply doing the same drop every time. Depending on turnaround times and numbers in the daisy chain as well, but the greater the quantity of retardant put on the fire early, the greater chance of getting it under control for the ground firefighters to put it out. 500lt is what we carried in our JetRangers back in the 80s and 90s, but with 5 or more in the daisy chain at least they had an effect. Sheer waste of money to be doing that sort of load with a 145 and multiple crew on board.
Do you have Sacksafoam to inject retardant into the bucket?