That 5% employer match is equivalent to a 100% return for putting in your 5%. That's an extra $2,425 per year in your pocket. Unless you plan to leave your current job for another that pays at least (2425+48500=) $50,925 per year I'd be putting in at least $101 each semimonthly paycheck to get the full match. Or $93.27 if you're paid biweekly instead of twice per month.
Your residual 11.7k in student loans is costing you roughly $526 per year in interest. Your 401k contributions are saving you paying taxes on $3936, which I estimate is saving you $984/year assuming you file single. Keep that in mind when evaluating whether or not to stop your 401k contributions, since you're currently saving more in taxes than you're paying in interest.
Unless you expect your income to rise dramatically in the future, I'd suggest raising your 401k contributions at the expense of your Roth contributions, until you get down to near zero tax liability. After that the only decision is whether you should be paying off the loan or investing in the Roth. One is akin to earning a guaranteed 4.5% before tax, the other is akin to earning market returns after tax. Probably a toss up. Just switching your Roth contributions to traditional 401k would probably save you several thousand dollars per year.
The real "optimal allcoation" is going to depend on your particular tax situation. If it were me, I'd be paying off that loan before doing any after-tax investing in a Roth, unless your tax liability is already zero.
