GS400: compatible 43-58mm step-up ring ??

[WorBry]

Anyone know if there is an 43-58mm step-up ring out there that will work with the Pana GS400 - i.e. will clear the manual focus/zoom ring, preferably without recourse to the rubber-band 'spacer' trick?
 
Presently I use the Olympus 43-55mm ring with a 55-58mm step-up for 58mm attachments, but I'm wondering if there might be a "thinner, one-piece" option.

B+W, Century Optics and Cokin do 43-58mm rings, but no-one stocks them around here and I'd have to order in on-line.
 
http://www.bhphotovideo.com/c/search?ci=420&N=4277997907+4208717617
 
One customer review of the Century Optics ring seems to imply that the 43mm back thread is quite deep (over 5mm), although the terminology with regard to male and female threads makes it a bit confusing:
 
http://www.bhphotovideo.com/c/product/224082-REG/Century_Precision_Optics_0FA_4358_00_FA_4358_43mm_58mm_Step_Up_Ring.html

Quote: "....The male threading is almost 3mm wide which won't completely screw into the wide angle adaptor I have (also Century Optics) and the female thread ring is well over 5mm wide"
 
Is it actually the back 43mm (I would call it the 'male') thread that is 5mm deep or the 58mm ('female') thread? Difficult to tell from the product image alone.   
 
Anyone using this ring who could confirm?   
 

 

[WorBry]

Contacted Century Optics who advised that the 43mm back thread is just 2.5mm deep.....pretty standard.
Ah well, thought I was on a winner there     

[Guy Bruner]

I had good success with the generic stepup rings from B&H Photo-Video.  They are also cheaper.

[WorBry]

Unfortunately, they dont do a 43-58mm though - max is 43-55mm. Guess I'll stick with the Olympus 43-55mm + 55-58mm combo. Mind you, a 43-55mm ring with deeper back thread wouldnt go amiss either. If you look at the Olympus ring back thread, there's little more than 1.5mm of actual 43mm thread there - the other 1mm or so being slightly-wider, non-threaded 'spacer'.