I have specialised all bases (on medium). I have one science base with 6 labs, like radar bases very easy to defend, because there is only 1 entrance (with advanced radar). I usually use 8 noobs to defend such bases, but I give them best armour and a combination of close/mid/wide ranged weapons. Important are 2 snipers that I mostly place into the power plant to shoot through walls at aliens strolling outside.
Exceptions are my dropship-bases, which are defended by experiencend troops. In those bases I have enough soldiers even when dropship is out, because of injuries and I use different specialists for different maps.
My workshop-base (with 5 workshops, stores and anti-matter chambers, disassemble is very fast) is surrounded by 5 SAM-sites, because I hate to defend bases with so many entries.
I only attack slow UFOs with stilettos (one in USA, one in China), but I need more since gunboats show up now (i think they are gunboats, haven't captured one). The other ones I get when they land. I discovered dragoon and that other vessel but have to experiment with them now.