Valve Crystal Oscillator Grid Current

[John M0GLN]

I've read through the book by 'J Douglas Fortune' again in hope of finding some crystal details but all he says is 'select for frequency', no mention of type or of holder, I have attached 2 more scans, one in which he talks about crystal current and the other showing the circuit of the valve oscillator he's referring to, this oscillator has 6L6 valve with a 150mA bulb in the grid / crystal circuit, I ran a 300mA bulb, the smallest I have from a variable power supply and it was barely glowing red at 150mA so I assume that the 150mA bulb in the 6L6 grid circuit is going to be passing at least 60mA to show some visible indication, now for me it's not so much where this current is coming from, it's obviously there in his circuit, but how can the control grid pass this current? The permissible control grid current for an 807 which is virtually just a 6L6 with a topcap is generally listed at about 5mA or less.
The photo in the scan does show the crystal holder he's using.

John