I don't think putting an extra half litre in will cause any damage as when filling on the level you can't get the recommended oil quantity in mines been inverted comma's over filled for years and no brobs
Welcome to the club
Im up in woodlands doncaster work as boilerman at markham grange nursery and steam museam we have a couple of meetings a year that camp out for the weekend with there scale engines
You will find the best place to attatch the tirfor is to the tree our other truck that you are useing as a anchor point attatch the end of the cable to your truck so it would be best to keep it in the boot
Ive just had a 110en replaced by insurance after having my tools robbed nice machine you will find that most clarke migs are piped for gas just need regulator and bottle dont bother with small bottles they only do 10 to 12inch of weld