I have no experience with a tagalong so can't recommend something specific to your set-up. I wouldn't think you will have any issues with a quality built 36h rim from Mavic/Ambrosio /H Plus etc. I've sets of hand built Mavic Open Pro and Ambrosio Excellight clincher wheels with both 32h and 36h rims on road bikes, built by Rourkes (Stoke), Pete Matthews (Liverpool) and built my own at Swallow Cycles Ironbridge using NOS Nisi tubular rims and never a problem and I'm 14 stone + . I've also used some cheapo Alex rim wheels on city commuter bikes and out of the box they aren't true and you can see poor manufacturing rim finishes (brake rub) etc. It depends I guess on how often you cycle etc, but good wheels do make a difference.