Fat Handle Tech (all brass):
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Ball End Tech (all brass):
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Later Techs with aluminum handles and Zamac top caps:
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In my opinion the Fat handle has the poorest balance, being slightly head-heavy.
The ball end Techs have better balance as the handle is solid brass, albeit smaller size.
The later Techs with the spiral/plaid aluminum handles and Zamac top caps are extremely light, balance well and still shave great. If the "dreaded Zamac issue" is a concern, these razors can be picked up for very little money and are often found attached to extra-short handles as travel razors in NOS condition. You could easily get a lifetime supply of these for less than $100.00. If you want light, that's the one I'd go for.
There were also Techs made during brass shortages.
This was made in 1951 with a brass head and bakelite handle. I found it too unbalanced. However when paired with a heavier handle it really improves performance.