Dimitri:
I may have spoken too soon - I was digging through my stuff last night, and could only locate one pair of the long braces I spoke about (which I need to keep for myself.) Also, the metal tabs aren't brass as I thought - they are a sort of "browned" metal (i.e.
not the dull blackened finish that marks web gear as definitely postwar. I have an unissued war-dated Canadian haversack which has similarly
brown-colored metal buckles and tabs ...)
I know I had several pairs of these braces to begin with, but at the moment have no idea where I may have "stored" them ...
Rather than rely on me as a possible source, you should probably keep looking - maybe check with Bill at Things Military, as he just might have long braces which you could add to your order ....
By the way, if the braces you've tried were only the "short" or "normal" length, you might just find that a pair of regular "long" (as opposed to "extra long") braces
may do for you, anyway - though they might not have as much "free end" as originally intended. P'37 web gear was worn fairly high - i.e. the waistbelt should be at the true "waist", not down toward the hips like we tend to wear belts nowadays. Also, the front tabs of the braces are not intended to reach the belt, but only to come down far enough that they will attach to the buckle on the top back of each basic pouch (in the normal configuration) - or attach to the buckle at the top of the strap extending up from "cartridge carriers" or at the top of the separate "brace attachments" used in other configurations in lieu of the basic pouches ...
You may know all of this, of course. (If not, however, feel free to ask for additional info or pictures to clarify what I am talking about.)
While I'm rambling: another thing I couldn't locate last night - which annoyed me greatly - is a pair of unissued, war-dated Canadian-made braces which are of the very first original configuration - i.e. consisting of separately marked "L" (left) and "R" (right) braces, one of which has a webbing "keeper" sewn to the inside of the "rear" strap at the point they would cross over in the back. The original regs called for the strap of the other brace to pass through this keeper (rather like you do with the tail of a necktie through the "keeper" usually sewn onto the back of the tie) - supposedly to stabilize the braces. Perhaps needless to say, this arrangement didn't really work all that well - different sizes and shapes of men meant that the keeper could well not be in the right position to be made use of (plus, using it added another step to the rather complicated procedure of assembling the webbing, and made proper adjustment even more finicky) so the keeper arrangement was not generally used, and the feature was eliminated from the design - so there was no longer a "left" and a "right" brace. Apparently, overzealous application of the revised regulations resulted in the removal of the existing keepers from many of the early pattern braces, with the result that such a "true pair" is quite rare nowadays. So it does tick me off that I can't figure out what I've done with some of this stuff!
Actually I do want to use this for the shoots that some people seem to do wearing WW2 gear and, the other reason I want a full set is for hunting, the small pack and the brace (which actually is too small to use as a sholder pack in my opinion as well, that brace does have a "keeper" loop though) that I have now I use for my hunting and hiking pack, its outlasted most of the other commerical packs without it shown any real wear and tear (got to love thick cotton canvas! 
