Re: ht leads
Yes - I've used the Lodge plugs and not noticed any problems. I've also used Bosch 4-electrode plugs and they were fine, and also the NGK equivalent. The P4 doesn't seem too fussy.
As for changing them...!! Use the original toolkit spanner as it's just the right length. Otherwise I found that your extension socket is either too short or too long to fit in between chassis rail and cylinder head.
You have no chance at the "Big H" for leads.
Also check your air filter and the oil breather pipes on the crankcase. Any blockage in there is going to make your boy a bit asthmatic.
No bullets for Chaingun..