Soilless/hydro is slightly lower. I like to shoot for ~6 just so there is a little leeway above and below. Some swear by 5.5-5.8 - probably needs a little extra Ca at 5.5 vs 6.0, so it can impact your overall concentrations and ratios that you eventually settle on.
Good soilless/hydro nutes will be ph balanced and buffered. Shouldn't need to do anything, but if you do, not too big of a deal either. Above all, be religious about the minimum 10% runoff. it's what maintains the balance in the rootzone and prevents buildup. The equilibrium that results in the medium will not exactly match your formula, but the consistency is the key. From there, any issue related to nutrients is fixed with a formula adjustmnet.