Help modify PSU!

[RollE2k]

Today i'm running this PSU below for my Mu-follower line stage, running at about 28mA fully loaded both channels
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I'm dropping the voltage over the regulators just alittle (about 30V) and have gotten hold of a new transformer with a little higer voltage (and more power capability).
I will modify my linestage to a parafeed and will be running 6n6p tubes so now the load will be around 80mA in total, as shown on the schematics.
the regulator before the LM317 is a MJ13005 (dont have any model in ltspice) and i want to drop the 300v down to 190-200v, which makes the MJ13005 running at around 7-7.5W which i guess is quite much/hot. Now if i would like the regulator to run cooler, would the best way be to change the D3 zener to a higher value? like 40V drop or so, or what would the best/simplest way be?

Thanks for all help in advice!

[Elvee]

Nothing you can do will modify the dissipation: you have to drop 100V @ 80mA, that's 8W.
You can modify slightly the way the power is shared between the transistor and the LM317, but that's all.
The simplest and safest way to dissipate power is to use a resistor in series with the input: 820 ohm or 1K will take most of the power at the maximum current.

Anyway, a discrete regulator using a MOS as a pass element would be much more robust, reliable, and could dissipate all the power by itself.
This example isn't more complex than the Maida, has similar performance and is more rugged.
Note that most of the components are unnecessary for the regulation, but they improve the survivability of the circuit.
You have to choose suitable transistors, these were the ones available in LTspice, but they are suboptimal.