Hey Doc, thanks for your wishes and kind comments.
The length of the handle on the standard Merkur once converted is around 84mm and weighs in around 110 grams, the aluminium one come in at the same length but wieghs in at around 84/85 grams. The long version in stainless has a handle length of 101mm and a weight of 116 grams whereas the aluminium one is the same length but the the weight goes down to 90 grams. I am currently working on a brass version, the lengths will be the same but the weight will obviously different. On a Merkur 500 the weight will increase to 113 grams over the stainless version of 110 grams. I am also working on ways of getting the weights very close to original spec, but it will take a little experimentation and time.
The Stainless material is 303, I can get a lower carbon content but the 303 gives better machining properties and easier polishing, plus it is also easier for the end user to clean and polish. I don't know about the aluminium, I shall have to check and see. But if the good doctor would like some 316 I have some in my stock ;-)
I work from a small shed and so I have to pick materials that I can cut on a small machine, hence the 303. For anybody else reading this 303 is a grade of stainless steel that has a small carbon content. It makes it easier to machine but is still stainless and will not rust. There is a common myth that stainless will not stick to a magnet, this is not true. There are 5 basic categories of stainless, and in each of them are are several sub categories. All have different properties and advantages/disadvantages. I could go into a whole lot of details but I doubt any of you are that interested, if you do take an interest just have a google and you shall find what you seek
PS
I almost forgot, there are 5 flutes on the knob at present. I could do more, or a little less but to me 5 looks the best. (yes I have tried others)