[tz] zic option for including data from a certain year onward

Hi, I think the tzdb is very good with its history. However, I would like to minimize the size and has been looking into how to achieve that. Will it be of any interest with an option in zic to include only data from a certain year onward? What is the best way? 1.? Remove the Rules and Zone entries not relevant for that year onward during the parsing. Tried this, but ended up with with some nasty warnings. 2. Make changes in writezone-function. Trying this now, but I am getting confused with types, omittype, typemap, and so on. It would be good if someone that knows the code can give me some hints if this is the right place to make such a change. BR, Christopher Wong