Despite the comments made on here by others I am willing to give you an overview of the improbables of answering your questions from an ex promoters point of view.
In 2018 my heat leaders in my championship team were earning less a than a certain rival clubs number seven. I had two riders on a ‘minimum guarantee’, i.e. if they crashed in heat 1 and didnt ride again then they got a minimum wage. One of these was to satisfy a work visa criteria. Some got a bonus if they scored over a previously agreed points score. Heat leaders got more than second strings and they got more than reserves. Travel was paid to all at the going rate of certain pence per mile.
Now all clubs pay different rates depending on their income which includes turnstyles takings and sponsorship. Some clubs did not pay their riders weekly, I did and I never not paid on the agreed pay day, some clubs paid when they had the cash to do so, some didnt pay for weeks.
The whole of speedways finances are a secret and a mess. No two clubs have the same income or outgoings because of stadium rents, riders wages, staff wages , maintenance costs etc and everything is dependant on regular home fixtures as you pay your own riders home and away so if you have one home fixture and two away, then you have three wage packets to pay but only one income fixture.
So the basic answer to your question is…..
depends on the club, the riders, the scores, the attendance, the sponsorship , the bills etc etc etc.
That is why Im an ex promoter !.