How to choose the series pass transistor?
Power dissipation ,Current ,Voltage and Safe operating Area .On the Ap note circuit life is good because the input /output differential voltage is only 2V7  so power wasted is manageable with the Husky MJE4502 on a heatsink .You want to increase max      current by 40% Which is not a show stopper .However your expected input /output differential will be more than 36V .This will call for many    Power devices in parallel .Your Calculated Heatsink will have to be much less than 1 Kelvin per watt which as a rule of thumb it wont be easy .Consider reducing your input volts .Prebuck works well for me .Some large off the shelf linear lab power supplies have automatic relays that step the tapped transformer secondary windings to save heat by keeping input /output differential volts not too high .