25c-NBOMe ≠ 2C-C
They're 2 different things.
And please, if dosage went wrong last time (sorry to hear) then don't try and lay blotters. It's quite hard to do it properly. I just lay individual chewing gum 'hits' every time I do this when me and my pimps hit the club. (e.g unable to take a needle-less syringe and vial and everything) You could lay individual blotter tabs, but why bother?
At any rate, here is what you should do:
First of all, you should really get a scale. I don't know what exactly happened last time, but it seems like it wasn't something you'd want to experience a second time.
However, that is pretty expensive and I understand if you don't want to spend $200-300, especially if you're hardly ever in a situation where you weigh your own drugs. We can minimize the risk, however.
We do that by getting some accurate form of measurement. 1ml syringe should do the trick. In that case if you drop too much of a liquid, we are only off by maybe 20-30ug of NBOMe. We also do that by making sure our solution isn't dangerously potent. For example if you take 5ml of ethanol, which gives you a ratio of 10mg/ml, then even the smallest of errors will give you much more than you wanted.
Starting with the actual laying of things, you first should check how much liquid a single gum/tab/whatever holds. A half piece of gum IME holds something like 0.1ml. Maybe a bit more, maybe a bit less. This determines how much of a liquid you should add to your 50mg of 25c-NBOMe. I'd add 10ml if you're going with the gum route. In that chase you get 5mg/ml, and you can safely/accurately dose. After that, just drop 0.1ml on a half-piece of gum, let it dry and you're all set.
p.s This is all given your vendor isn't overly generous and decides to give you double the NBOMe. Hit the web to see what a comparable amount looks like.