I would use a Linkwitz-Riley filter, as this sums to unity gain at the crossover, and doesn't require phase reversal. Also, unless you have a good reason not to do so, use the 48dB/octave setting. This will remove further any out of band signals and give you less overlap that can colour the sound. Not serious, but if you have the option, you might as well use it.
At a loss for something to do on Bank Holiday Monday 29th? I will be having a leisurely day of music and chat. Room for 10 or so. Bring some music on vinyl and/or CD.
hap hazard (Des)
Depends. Some go and show little or no damage. Other have white marks on them and others have the 'metalwork' damaged. With a preamp and the 6H30s I would not expect to see much damage although flash/bang episodes can be more dramatic. I hope the flash/bang is not due to capacitors being taken out or a resistor exploding. If the boards look OK then you may be in luck. So with any luck it is just a valve that failed and once replaced everything should be OK.
Fortunately there are loads of live versions of this, lots with video. Do a you tube search, there are quire a few there. Not sure, but I think he may have done a whistle test version too. For me its a late night classic..amazing.