putting a 5 string set on a t-40

I'm in an industrial band. At the moment i am stuck using my Ibanez Gio because and only because It can reach low B. One of my friends told me i should try putting a 5 string set on my Peavey, but I am afraid to waste money on buying strings that won't fit right. Has anyone tried this?

I did this 20 odd years ago and I can tell you what I did. I think filed out the bridge saddle a little to accommodate the larger string and I recall filing out the nut.

The question is do you want to play the whole thing tuned down BEAD or something else weird. If you aren't skilled at doing your own tech work, I'd have someone else do the work but here is what I'd do now.

Buy either a 5 string set or just the 4 bottoms strings a replacement nut so you don't have to wreck the vintage one. Have the nut installed and filed out by a tech to fit the larger strings. Depending on how much wear the bridge has there shouldn't really be any issue with the larger strings. The bridge saddle thing might have been because I needed to widen a hole to get the string through, not because of any issue at the top where the string goes over.