The short answer is that 150 should be fine for a gnome at this point in the age. While higher NW/A usually indicates a stronger prov (given the race), the highest NW/A provs *usually* have gotten there either by being inefficient, or being chained.

If you want to get really analytical, what you look for is high MPNW (Military Per NetWorth), or high OPNW at a fixed DPNW. This can be achieved by having lots of military - or lower NW. This measure is why 200% Pay Rate and TGs are so important - both are "free" offense. I claim forts are underused for the same reason.

Gnome achieves mediocre MPWN compared to the main attackers (Avian, Human, Dwarf) but have some other benefits that might make up for that... in particular on a kingdom scale they give *everyone* +3% offense without risking the random factor.

Don't go crazy with the homes or very high DR - while homes are good, TGs/Forts are *usually* better. High DR requires more banks - taking away from your TGs, *and* lowers BE directly, hurting everything. So while 55-65% is needed to compete - having 80% DR will break your econ, even if it makes your NW look good.

The biggest thing for (good) high NW/A is housing sci: more housing -> more troops -> more NW. But because the "land %" of your NW goes down, your MPNW also goes up with housing... at least until somewhere around 10,000 bpa.

One other little note - high NW/A acts like free GS from the enemy's point of view. Conversely, low NW/A is like extra gains for the enemy. The impact on you will be the same, but if trading land those few %s will eventually start to matter.