As someone who plays Fender Ps, Js, and 5ers - *I* would recommend getting a used sr505, to see if you'll stick with playing a 5er... It's a good enough instrument to give you a feel for it, yet won't hurt money-wise if things don't work out... Other decent economical choices would be the import 'Ray 5, or Spector's Legend 5 or Schecter's Stilletto 5s for 35" 5 strings...
Switching back and forth between Fender 4 strings and 5ers, *for me* EBMMs work extremely well for 5ers - they're also 34" like my Fenders, have a moderate 17.5mm spacing at the bridge, and a neck that's not too wide... I've never cared for Fender 5 strings, since their necks are too chunky for my tastes, and their B strings have been underwhelming to me...
Lastly - make sure you stick with it atleast a couple of months, otherwise you're probably wasting your time... It took me that long to quit screwing up and getting the B string by mistake - and close to a year before I was really comfortable on a 5er... BUT, the payoff has been well worth it, and I wish I had done it sooner...
- georgestrings