Well, I took the bike out today, and it feels fine to me. No more flex than I would expect (and that with me putting my feet on the down tube, one hand on the seat post and one on the stem and pushing and pulling like mad.
I even rode it with the bolts loosened, just to see.
I decided to add frame clamps either side of the main clamps (the kind that hold brake cables onto frames - but I will try and go for something more sturdy - I have some old parts from a triple crown suspension fork that fit perfectly - ahh, standardization). I was also riding without an insert, which I will add for peace of mind to the downtude.
All in all, It rode well.
I have to strip the frame and build it up again with beter parts to get a true feel, but so far, I'm happy with it.
I was wondering whether it was a redundant exercise, as my tourer is double butted 531, and probably wouldnt have the strength in the tubes when cut to survive, but then I weighed the cut bike, and it was actually lighter than my 531 tourer, and by about 6kg. Bizarre. Maybe its becasue it's a smaller frame and had no rack, but then again, it has, at present all steel everything - wheels, chainring, stem, so depending on the ride, I may just stick with this.
All I'd need is a bag that would take it now.