Personally. I'll try to centralize tools and scripts - t.i. to write them (at least as a copy) into oldwikisource, then importing them from there. The problem is, that documenting and centralizing seems time consuming at the beginning for enthusiast nut unexperienced "programmers", but experience tells that some time gained at the beginning implies lots of wasted time as soon as things become complex....
A problem is that js can be really centralized, we can really read a unique centralized script; this, IMHO, is not possible with templates and LUA scripts, since they run as specific project pages. So, aligning versions is a serious issue.
Alex