Don't forget that the oil has to be changed at the end of the three hour break-in period to remove all the small metal fragments. Then again at 20 hours, then at 20-25 hour intervals.
And, now this may be a stupid suggestion, but if you have 6 projects and no money, might I suggest that you sell a few projects to someone who can properly maintain them to have some money. I'm 16, and I have 4 karts and a minibike, and I'm cheap and a little broke. Only the minibike and one kart (my streaker) run, so for the others I prioritize and swap parts between things, in a way that makes sense. For example, a 30 series wouldn't work on my Manco because it needs a jackshaft on a backplate, however it does work on my minibike which had a jackshaft on a backplate. And an oil change literally takes less than 10 minutes, so not having enough time isn't much of an excuse.