There are various things you must match when fitting a non-standard plug. Key aspects are heat range and projection of the centre electrode.
Obviously physical stuff like thread diameter, thread length, and possibly hex size if space constrained. Some plugs have fixed terminals, some screwed, check what the cap/coil requires, usually easiest to match if it takes a terminal rather than a thread (unusual these days in a production car), you can use fixed or screwed terminal no issues.
If the heat range and projection are correct I'd say you'll be OK. Leave the plug gap at what it comes as (check but don't alter unless absolutely necessary). Precious metal electrodes are smaller diameter, concentrate charge, and thus reduce the spark voltage requirement compared to a bigger electrode. You can offset this with the bigger electrode by having a slightly smaller gap, otherwise it will tend to load the high voltage side more, with possible reliability aspects. The difference between 1.1 and 1.3mm is unlikely to result in any real perceived effect. Of course you will lose any slight benefit in combustion stability and durability of the precious metal plugs, but your reason is cost so that's your compromise.
Try it and see if you can tell any difference, I suspect you won't in real world use.
In cases where the projection is changed significantly it is quite possible to run into cold starting or fouling issues, I know of cases where people have used non-projected iridium plugs in place of projected nose standard items (due to first sight compatibility aspects) and had cold fouling even though the heat range was the same.
You could check the Denso equivalents, they are often cheaper than NGK here in the UK, possibly also in NZ? It could be a Denso K20TT or IK20TT, but you need to check for yourself.
https://www.gsparkplug.com/ignition/spark-plugs?find=honda-2008-jazz-ii-petrol-1031316089(PS - I worked in engine design/development for 40yrs).