I have only collected in California and Arizona and each species is slightly different so I'm not sure about L elaphus and D tityus. However, if D tityus is similar to D grantii as far as attraction to lights, then metal halide would be much better than black light for D tityus. I have a friend that collects D tityus each year and he goes to gas stations, convenience stores, schools, etc. anywhere there are big HID lights. I do collect L mazama and they come to black lights pretty well. Bugboy collects a lot of L elaphus, so he would know the best method.
To do a HID setup you have to do a little bit of handy work unless you buy it from Bioquip and its already put together but its really expensive from Bioquip. Its nothing difficult at all but a little bit of wire splicing, mounting the mogul socket to the tripod, etc. There are instructions online if you google it. There are many people on this forum who have done it so we can try to explain it. I'm not that good at giving instructions for things via text. It would be easy to show you.