Rear Wheel / Wheel Set for 250 Pound Rider
At risk of hearing the saying, "You can have it good, fast, and inexpensive... Pick two.", I'll ask for some advice on wheels.
The bike is a ~10 year old 61cm Cannondale Synapse. I'm still using the original Shimano RS10 wheels (10 speed ultegra cassette), but at least one of the spokes is having issues (loosens up) and the wheel won't stay in true after I ride it (had them trued last week to fix a rubbing issue, and the problem returned within 40-50 miles).
I'm 6'5" and trending towards closer to 250lbs than I would like right now. I've been off my bike for a few years, but have started riding again in the last 4 months. I'm currently riding ~3 days and 50-75 miles per week, but may start to push that out to 100-150 if my schedule allows.
I've seen Ksyrium wheelsets in the $500-$600 range and I understand they are an excellent wheel for that price point, but are a little spendy for my current bike budget. They also give a weight rating (rider + bike) of 265lb, and I'm a bit over that. They're not completely off the table for me, but I'm resistant to spending more on wheels than my bike is probably worth.
I've seen lots of sales online right now, including some RS500 wheels for under $300 shipped, but they show a max rider weight rating of 220. Other wheels I'm seeing online have pricing in the $200-$300 range, but don't show a max rider weight. The guy at my LBS (who trued the wheels for me) suggested this issue may come back and that if it did I could either rebuild the wheel or get a new one - he commented that rebuilding was not a great option for this wheel, but that he could do it for about $150 (I have no idea what goes into rebuilding a wheel at that price). He said they could build me "a good rear wheel" that is better suited to my larger stature for about $300, but noted that it would come at some premium on wheel weight. They were busy and they were just fitting me in, he and I figured I should try the wheel out again, so we didn't get into specifics for either option.
So here is the question, what do larger riders consider the "Best bang for your buck" rear wheel / wheel set, balancing cost / strength / weight of the wheel?
To add more confusion, I currently run tubes. I've been told (by nearly everyone) that I should switch over to tubeless. What do other Clydes on here think of that? I'm guessing if I wanted to go that route I would need a new front wheel and couldn't get away with just buying a rear.
Thanks in advance for the input.