My original straight shaft that i bought for my Pulse machine is still going strong,it was made by rods_by_plugger,i then was able to use that as a basic design for all my other straight shaft conversions,for a batch of 3 straight shafts i but a 1 mte length of either alloy or carbon fibre tubing.This can then be cut usually into 3 equally sections for the top shaft.
Then i use the universal shaft clamp once again from rod_by_plugger,other makes are also available on Ebay,this then gives the ability for wuick change over of coils if need be,the middle or bottom rods i have recently been using the 33'' Whites tallman bottom rods.For the handle although alloy bike handle bar extension do work fine they can be slightly heavy,so like Sven i also use the Minelab nylon handle nas they are very strong and of course dont rust or rot,the specific one that are used are the ones for the Sovereign straight shaft and not the GPX ones as the Gpx ones come with the expensive push button on the end.
The Armcup that i use is the Whites one that is used on the DFX/MXT and also of other Whites machines,these also have the armstrap as well.
Although not possibly the cheapest straight shaft options,as folks can also use other things laying around the house or modify other items to make a shaft,as long as it works and it makes you happy use what ever you like.The bottom line a shaft is basically just for holding the coil and control box on,in the case of my Deus i carry the controller in my pocket and just use the shaft coil and armcup,this is ultra feather weight detecting.
The whole reason of going down the straight shaft route was mainly i hate 'S' shaped shafts,also i wanted drastic weight reduction as i have had back problems in recent years,and even using my T2 i needed to cut down as much weight as possible.
In the last month after doing the various straight shaft mods,on 4 of my detector or weight reductions methods i am once again able to swing a detector for most of the day,when before it was just about 3-4 hours then i had to throw the towel in because of back pain.
These are just my methods and how i over come weight problems while detecting.