This was what I had originally done, however this applies to all interstitial journals, rather than one or the other.
Here’s what I tried to do for reference,
Inside of $:/plugins/kookma/kara/macros/add-items-interstitial
\define kara-add-item-action(timeFormat)
<$let
note-time=<<now format:'$timeFormat$'>>
item = {{{ [<tempTid>get[text]] }}}
newItem = {{{ [[*]] [<note-time>addprefix[<small>]addsuffix[</small>]] [<item>] +[join[ ]]}}}
newblock = {{{ [<dblock>addsuffix<newItem>addsuffix<lbr>] }}}
>
Inside of $:/plugins/kookma/kara/macros/add-items
\define kara-add-items(format)
<div class="kk-kara-header-ui">
<div class="kk-kara-header-textbox"><<kara-input-item>></div>
<div><$button class="tc-btn-invisible" actions=<<kara-add-item-action timeFormat:"$format$">> disabled={{{ [<tempTid>get[text]!is[blank]then[no]else[yes]] }}}>{{$:/core/images/new-button}}</$button></div>
</div>
\end
Inside $:/plugins/kookma/kara/macros/interstitial
\define interstitial(tiddler, showInput, focus:"yes", mode:"" format:"0hh:0mm")
\import $:/plugins/kookma/kara/macros/definitions
\import $:/plugins/kookma/kara/macros/add-items
\import $:/plugins/kookma/kara/macros/add-items-interstitial
\import $:/plugins/kookma/kara/macros/disp-items-interstitial
<$let tiddler={{{ [<__tiddler__>trim[]] }}}
src= {{{ [<tiddler>!is[blank]then<tiddler>else<currentTiddler>] }}}
dataBlockStartDelimiter ="@@.interstitial"
dataBlockEndDelimiter = "@@"
tempId={{{ [<tiddler>!is[blank]then[interstitial/$(currentTiddler)$/]addsuffix<tiddler>]
:else[[interstitial/]addsuffix[$(currentTiddler)$]] }}}
editTextPlaceholder="add new interstitial note"
focusStatus=<<__focus__>>
displayMode={{{ [<interstitialDisplayConfig>get[text]] [<__mode__>] :and[first[]] }}}
lbr="
" >
However I realized that I can’t really pass along the format to kara-add-item-action parameter, so I’m not really sure how to proceed
I eventually just cloned the interstitial tiddlers and made a second version as <<log mode:"reverse">>
that used a different time format from what kara’s interstitial uses.
Edit: Made a new topic for this instead of continuing the old one.
Edit 2: Unfortunately, I don’t think I’ll be able to make it work as I’d like it to, I haven’t managed to find a way to set a different time format for each interstital journal