Clock hand matching

[dnhb]

I have a French 8-day clock (see my "charity shop purchase" topic) with just an hour hand. I'm considering  - as a learning opportunity- making a minute hand to match it. I'm thinking its form could be derived from the hour hand by proportionally(?!) extending the latter's outline as a first step. But are there any rules of thumb which relate the size & shape of a minute hand to a given hour hand which would help in refining such an initial outline ?

[oldhippy]

I have just looked at the charity shop purchase" topic. The hour hand is the style spade very popular. You need the length  to be just inside the outer line of the minute line on your clock dial.