Top man! Thank you.
You're a scholar and a Gent! Thank you for testing this for me and I genuinely appreciate you suffering through a shave to share this.@Boycie83 - I did a comparison shave last night and can confirm that the Windsor shaves much more roughly with the older cap attached. There’s much more blade feel and some noticeable chattering. Whilst it will work, it’s not a particularly nice combination.
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I’ve done a side to side comparison photo of the two caps and, as you can see, it’s not just the length covering the blade tabs, the widths between the two are also different.