O.k,at first,these are the Output Jacks,connected to Output Transformer,not the Input Jacks.
Those Types are the same as you use in your 18W Build.
To make it clearer,what those 4 Contacts on it are for,tak a look at the Top Side of the Jacks,you will see,there are 2 Permanent Contacts, and 2 Switchabel Contacts,them are "Opener",if you put in a Jack Plug,the 2 Contacts are opened.
So you have to link all 4 Contacts from the Ground Side,but to use only the 2 permanent Lugs where is the Tip connected.
Which of them are the permanent contacts,you could seen for example on the Top side from Jacks,if you put in a plug,the contact lift´s,and only permanent Lugs are connected.You could check it too,with Multimeter and the "Beep2 Function.
Those Jacks are also possible with 2 more Lugs, those are Stereo Jacks with Switch Contacts