Optimizing aircraft library loading time?

Hi all! I've searched quite a bit all over the net for this specific information, but didn't found a precise answer. I have FSX-SE, with quite a number of additional aircraft, majorlly freewares but also a number of payware from Steam, and I started to get increasingly long time to load the aircraft library. Of course I was expecting this, since I don't have a high performance machine (but I got quite a good FPS count during the game). The startup of the game is also slow, but it doesn't bother me. What's is really annoying is the time it's taking to open the aircraft library (over 1~2 minutes everytime). The hard disk is defraged, and a SSD drive is out of question now (specially because of the insufficient size). 

I've done a lot of cleanup, removing aircrafts I didn't use and specially removing liveries/textures I didn't use (I like the quality of the textures of the "megapacks" available, but ended up using like 5 or 6 liveries out of 20, 30...). 

So finally my question: I just deleted the undesired texture folders to reduce the number of options of each aircraft, with the hope of reducing the loading time, but I'm not very happy with the impact. So I have to also edit each aircraft.cfg to remove the liveries from there? I've done that to some, but with no impact as well. So I'm wanting to know what is the logic or path that FSX follows when it try to openthe aircraft library, in attempt to optmize it. Does it search for all the folders and subfolders over the SimObjects folder? Does it inspect each aircraft.cfg everytime? And finally, does it check the status of the purchases each time with Steam?

I even thought about creating two Aircraft folders (like one aircraft-copy foder), one with the ones I use frequently, with very few aircrafts, and one with "the rest", and keep renaming the folder each time I start the game. It's a pain, but anyone ever tried this? I've done this before with other games (like my list of cars from Assetto Corsa) with success.

Sorry for the long message and thanks in advance for the help!

Best regards,

Adriano