You could really make that type of beer with any yeast including 34/70, etc. If you would like your lighter beer to have 'less-character' than your Czech beer, I would suggest using something like S-189. It will ferment clean and it will not leave as much yeast character in the final beer. Use a malt with less character as well (Rahr pilsner, Briess, maybe Swaen from Holland) along with a decent percentage of corn. Use the proper water (soft, calcium to about 40ppm, a small amount of sulfate is okay but don't go above about 25ppm or so) and then use one hop addition (something clean... Magnum, Hallertau, etc) at the start of the boil to get to somewhere around 18-20 IBUs. The S-189 is very clean and has less personality than 34/70 does and all of that sounds a bit like Stella to me. When I drink a Stella it seems very fizzy, very bland and flavorless. I'm not opposed to it but I rarely drink it. Also, I'm not saying S-189 is the PERFECT choice but I think it's a good choice.