When it comes to customizing, never keep all your eggs in one basket.
Order small and have a backup plan.
Sooner or later, the Custom seller is going to have so much work that the gears break down. The best thing to do is think of the person doing the work and order responsibly.
That way if something tragic were to happen, you are only out $20 and we don't have any Suicidal Resin pourers out there who got in way over their head.