Budget 4.0 surround setup, need advice for surrounds replacement/setup

So I finally got my super low budget surround 4.0 surround system going, and here are the current components:



Receiver: Onkyo HTR-560 (I believe this came from a HTIAB)


Fronts: Rogersound Labs 3600 Studio Monitors (These hit just low enough, but they seem to be unbalanced. Currently setup with 1dB difference on my receiver)


Surrounds: Bose 101 Music Monitors (These are the only speakers I had lying around, and I guess they're better than nothing...almost)



So these surrounds just don't sound great, plus they are at different distances from my prime listening position so the sounds always seems off. My room is tiny so the right surround is 1.5 to 2 feet away from my right ear and the left surround is 2.5 to 3 feet away from my left ear, with the fronts about 7 feet or so away. I'm still constantly changing the speaker levels so I can't remember its current dB difference but I think the crossover is set to 150Hz which might need adjusting.


There's no way I can make room to shift the RSL's to the back and get new fronts at the moment, but I do have options. My friend donated to me a pair of old Denon USC-150 and a pair of Mission 8VET bookshelf speakers (which some suggest are rebranded as Denons or the other way around). I don't know too much about them and I've yet to plug them in but will be doing so soon once I remove the wall brackets from them. I'm almost certain one of these will do the job better than the Bose speakers I have.


I have two main concerns:


Is there any way (through a receiver setting/tweak) I can get the two surrounds to sound like they are at equal distances or does that come down to speaker selection mostly? I'm missing the calibration mic and have been adjusting speaker levels manually, but I also understand this receiver is entry level...and old.


Does anyone have experience with either the Denon or Mission speakers and can offer any advice on their setup and usability in a surround setup (If I don't use them for my system, they're going into a different living room surround system that my roommates can use)? I've also been considering Dayton B652 or those Monoprice satellite speakers that come in their model number 10XXX 5.1 systems.


Any help is appreciated