A question about Personal Loans

[Nikolai Matveev]

I have a wedding planned for the end of March. I want to get a personal loan in order to pay for it. 

I make $58,000 a year. I don't have any car payments already paid my car off. I pay $875 and rent. My credit score is somewhere in the 730 to 780 range depending on where you look. Fico says I'm 786 while another one says I'm 732 which dropped from 754 because I added $750 to my credit cards (which I since paid off). I have $5000 credit line on 2 different credit cards which I keep close to 0% at all times. 

I have been with the same bank (Wells Fargo) for the past 10 years. They have my automatic deposits from the same job for the past 6+ years. The one I'm working at now. So it wouldn't be hard for them to verify my income is what I say it is.

I don't have any collateral to offer I would be looking at an unsecured loan.

I would like to get $15,000-20,000 if possible. But I'm not sure how much I can realistically apply for. I want to do a long term payment plan because I know I can easily afford $400-500 monthly payments. I would likely pay it off much faster than the actual term.

Someone suggested getting a bunch of credit cards instead. But I'm worried that trying to apply for say $20,000 worth of credit limit would do a lot of damage to my credit. Nor do I even know if it's possible. Most of the pre-approved offers I get only have like $1000 credit line in the beginning. I don't think its wise to open 20 credit cards. 

So I come to you good people for advice? Can I talk to a Financial specialist about this? 

Thank you ahead of time for your help.