An argument from basis.

[genkaus]

1. Honour to objectively exist in some degree must have a basis for all possible degrees of honour.

Not necessarily. We can set an arbitrary standard - like when we did with 1 meter - and measure everything as its multiples or fractions.

2. The most honourable possible being is the only possible basis for all possible degrees of honour.

Wrong. As shown earlier.

3. Objective honour exists.

Does it? I haven't seen any evidence of that yet.

4. Therefore the most honourable possible being exists.

Since all three of your premises are wrong, the less said about the conclusion the better.