Honestly, a 500-watt rms amp into 4Ω should be fine. You can get an 8Ω 210 cab for that it will about 250-watts into it for small and medium venues. Then buy a second 210 and your amp will put out an additional 250-watts into that one when you need get more volume. Two of the 8Ω 210 cabs is a de facto 410 cab and a 500-watt 410 cab should take care of just about anything or place you'll play. Some outdoors without FOH support might be a problem and some music festivals may be a problem, but music festivals always seem to have FOH support and you should have plenty of stage volume with your rig.
Having said that, I had too little amp way back in 1971 for the gigs I was touring with a nightclub band and the guitarist and keys both upgraded their amps to 120-watts amps with 412 cabs at the same time. My poor little amp with its 212 cab just couldn't keep up. It's no fun to be told, "you need to turn up" by the rest of the band when you are maxed out. I ended up buying an amp that had 4 times as much power as the one it replaced and I never had another problem.
It had a powered 215 cab with 4 round ports alongside the speakers and I could only turn it up to #3 on its dial (9 o'clock) indoors in most places and it would flap my bell bottoms if I got within 3-feet of the cat at that setting. I was never again told, "you need to turn up". I was touring at the time so it was worse than embarrassing. I vowed never to be in that position again. So, currently I have two 800-watt amps one a class A/B Eden amp and the other a DNA-800 amp that puts out 800-watts rms into 4Ω or 2Ω and has a built-in compressor with adjustable threshold and ratio.
A 500-watt amp is probably all I really need. But, with my cabs, I KNOW my 800-watt amps are more than enough for any job. I even get told to turn down at music festivals when I move the master up to 10:30. Street price on my DNA-800 amp is $799. If the 500-watt amp you're looking at is within about $150 of the price of the 800-watt one, I'd go with the 800-watt amp. In any case, you'll probably opt for an 800-watt one down the road anyhow.
Having said that, I had too little amp way back in 1971 for the gigs I was touring with a nightclub band and the guitarist and keys both upgraded their amps to 120-watts amps with 412 cabs at the same time. My poor little amp with its 212 cab just couldn't keep up. It's no fun to be told, "you need to turn up" by the rest of the band when you are maxed out. I ended up buying an amp that had 4 times as much power as the one it replaced and I never had another problem.
It had a powered 215 cab with 4 round ports alongside the speakers and I could only turn it up to #3 on its dial (9 o'clock) indoors in most places and it would flap my bell bottoms if I got within 3-feet of the cat at that setting. I was never again told, "you need to turn up". I was touring at the time so it was worse than embarrassing. I vowed never to be in that position again. So, currently I have two 800-watt amps one a class A/B Eden amp and the other a DNA-800 amp that puts out 800-watts rms into 4Ω or 2Ω and has a built-in compressor with adjustable threshold and ratio.
A 500-watt amp is probably all I really need. But, with my cabs, I KNOW my 800-watt amps are more than enough for any job. I even get told to turn down at music festivals when I move the master up to 10:30. Street price on my DNA-800 amp is $799. If the 500-watt amp you're looking at is within about $150 of the price of the 800-watt one, I'd go with the 800-watt amp. In any case, you'll probably opt for an 800-watt one down the road anyhow.
