No small measures with you that's for sure i.e. that's quite the cocktail of Benzodiazepines let me tell you! Lol!
And six years: that's a pretty long time so this ain't something that's going to be taken care of and nipped in the bud within a few days I assure you. You're probably looking at weeks, probably months, and maybe even a year or more before you're clean (unless you wish to end up being REAL uncomfortable and very sick and putting yourself at serious risk by going cold turkey or tapering too quickly).
As for how long you could take Valium again before coming dependent again: I cannot answer that. I can tell you this though (and this based on very recent personal experience): once you've built up a tolerance to these things (which you will most definitely have done by now) then when you start taking them again the tolerance seems to return WAY much sooner than when you started taking them in the first place. Note of course that there's a difference between tolerance and physical addiction (although the argument could be made that once you've built up a tolerance you already have a dependence or physical addiction)
Any chance you could simply taper off the entire lot and stay off permanently? Just a thought. Problem with benzos. (as wonderful drugs as they may be) they do not solve underlying issues or problems. They simply mask them while you're taking them. They don't cure anything. And in some cases e.g. anxiety they can even eventually magnify the underlying causes for taking them in the first place or result in something called "rebound anxiety" i.e. the anxiety returns in spades once you're off of them.
As I try tell everyone though: it's different for all. And there's no race to try and get off these things as quickly as possible i.e. there's no prize at the finish line for having had the quickest taper than anyone else. And there's no shame in drawing out your taper for a longer and more palatable and safer tapering period than the next person.
I'm not sure how much or how little you know about these little wonders but below is a link to everything you could possible want to know. They even have their own forums on the topic. As for all the information contained on the site: what you're really looking for is a document known as "The Ashton Manual". It describes different benzo. equivalent dosages, methods of and timetables for tapering, half life of the different benzos., etc. etc. etc. The information can be a bit overwhelming (or uninteresting if it's not your thing in life to know everything there is to know about Benzodiazepines) so "The Ashton Manual" is the shortcut really.
THE RESOURCE SITE FOR INVOLUNTARY BENZODIAZEPINE TRANQUILLISER ADDICTION, WITHDRAWAL & RECOVERY
THE ASHTON MANUAL - BENZODIAZEPINES: HOW THEY WORK AND HOW TO WITHDRAW
As I note time and time again though: I'm no big fan of changing from one benzo. to another to ease the taper. But that's just me and based on personal experience. It's not for me to question the Professor. And in a case like yours: I'm not quite sure where you'd start either and substitution during taper may be necessary (as opposed to it being an option).
If it's any consolation: there's people around here that have been on various benzo. cocktails for TWENTY years and have successfully tapered and not relapsed and from what I gather would never go near the things again even if you paid them to do it!