I created the following activity diagram using plantUML:

@startuml


title Usecase <<Place Order>> Success Scenario 

skinparam ActivityBackgroundColor Business
skinparam ActivityBorderColor Crimson
skinparam ActivityBorderThickness 2
skinparam ActivityFontSize 14
skinparam ActivityFontStyle normal
skinparam ArrowColor Crimson
skinparam ParticipantPadding 200

|Supplier|
start
:Visit Offer Details page;
|System|
:Display offer details;
|Supplier|
:Click "Placer Order" button;
|System|
:Show order form;
|Supplier|
:Specify desired quantity;
:Confirm order details;
|System|
:Save order;
end;


@enduml

Which compiles to:

The problem is that the generated arrows are too short which, IMO, makes the diagram ugly.

I consulted the answers to the question How to make PlantUML left/right/up/down arrow longer? but they seem to use a syntax that is incompatible with the way activity diagrams are currently edited in plantUML.

I also went through the All Skin Parameters page in the plantUML docs, but failed to find any option that allows changing the default minimum arrow length so I was wondering if there are other means that could be employed in order to achieve the same result.