Jeff Evans
I don't agree that producing classical music is any easier on monitors than anything else. I have produced many orchestral simulations so I know what it is like dealing with the raw materials that lead up to a final orchestral mix. The orchestral bass drum for example or the low arco double basses have the potential to make a hi fi speaker woofer move about three inches!  Sure when the whole things is mixed, mastered and the compression processes come into play and the bottom end is under control yes it might be a good time to check a mix on them for sure but not much before.
 
I really doubt that many studios are using them as their starting point or their main speakers. They may have them in there for checking reference and mixes on them. I use small hi fi speakers myself to check mixes on but not until everything is very well mixed and mastered eg as if you were playing a standard CD on them.
 
Starting with a home theatre store in my opinion was not the thing to do. You should have started by going into a store that featured active studio monitors that are generally used for DAW work first. I have heard very very good things about the Presonus speakers too and it would have been smart to seek them out and give them a decent testing before doing anything else.
 
When I started producing electronic music many years ago I used my Hi Fi speakers as the main monitors. I had a pair of British Leak speakers that even featured a 12" woofer and a decent mid range and tweeter as well. (they handled tons of power too and I had a decent amp driving them) They did not last long though only about a year or so, I basically destroyed them over a period of time. And I was not pushing them that hard either. It was not until I got a proper pair of active monitors that my mixes started sounding much better and they lasted a much longer time. They are virtually indestructible. Especially now they are even better.

Jeff Evans
I am not trying to make you feel bad that is for sure. I hope they work very well for you. Well I think there are few things you can do:
 
1  Keep an eye on your overall listening level. I use a SPL meter in my studio and keeping things at 85 dB SPL is a very smart thing to do. It is a gorgeous volume and not very loud at all but still nice and loud enough to hear things very well. I can crank my speakers up to past 105 dB or even 110 dB SPL. You basically will never be able to do that though.
 
2  Keep an eye on your woofer and see how far it is moving. It is direct feedback as to how hard it is working!
 
3  Not sure you can do this but if you had a spare stereo compressor you could press into service it might be an idea to have in the signal chain just before the power amp and set for limiting. Fastest attack and threshold high so under most conditions it is doing nothing and will not influence your sound (other than the sound of it though) If you do accidently produce a very loud sound (Every one here has done it and I have done it many times!) it will catch it and reign it in.
 
4  Be vigilant about your switch on procedure and make sure your power amp goes on last and off first. This can be a problem. Like my digital mixer sometimes produces the most horrendous noise if I accidently have my main active speakers on for any reason.

SuperG
They're definitely some nice looking speakers. I don't suppose a they'd be normally be used for mixing - they're probably too sweet sounding. But a mastering studio might have a pair - the more speaker sets they have, the better - always good to have final checks auditioned on several different sets of consumer speakers to see how a mastered piece plays.