Ship with Seat Loose ??
This may be a little advanced for you. But if you are a gear weenine like I am then you might like the option of being able to make some mods on your own. One relatively easy thing to change is the seat placement and even the seat itself if you choose.
QCC uses Plexus to glue the seat in place. This is a very powerful marine bonding agent. The bond is stronger than the surrounding area. So if you decided to make changes in the future you would have to very carefully crack the Plexus seal. This is not easy and can easily lead to damage.
You may want to have QCC send the seat loose. They will do this for you. Then you can use some other less permanent method to hold the seat in the boat like Velcro or a less tenacious marine adhesive like Boatseal or Sikaflex.
I like the QCC seat. I never had any comfort issues with it and it is very light. But I prefer its location a few inches forward. I also have experimented with sliding K1 seats.
Anyway, experimenting with this stuff is premature at this point in your paddling career. But, it might be something you would enjoy after some experience.
Please feel free to email me directly if you ever have any questions. I may be the only person who has owned and paddled all three versions of the QCC700. I also have worked with John Winters to design a USCA optimized sea kayak that has won a number of USCA championships and other races. I have lots of seat of the pants experience, design insight and plenty of opinions too 
I donāt own or paddle the QCC700 anymore as I have moved into surfskis. However, the QCC700 is an excellent starter boat for anyone who perhaps sees themself heading in this direction. If this may be you, then you should be careful who you listen to for advice. There are many who would rather see you move 500 years backwards in technology & technique.
Jonathan
What I have in mindā¦
ā¦ is in some ways a bit more of a decked beginner/intermediate ski than a ruddered OI - and somewhere in-between on stability. More LV and rollable (including suitability for Greenland ātricksā) than something like an EFT - and with more intimate contact/feel - but still able to work legs and have decent padding form with all paddle types.
Going even furtherā¦
ā¦ just put in a full ski style cockpit and bailer ala Van Dusen Mohican, Think FIT, or the designs from down under that originated thisā¦
Funny you mentioning about the 700 continuing to turn. I thought it was me for a while (rudder folks notice this?). Iāve learned to sort of hip snap/wiggle my way out of it when it does this -sort of un-initiating the turn or re-initiating straight line travel. Easier to use some body action than just paddle and seems to break whatever flow pattern is at work.
Seat moves - some caution/background
Folks should be careful to add which version(s) of the 700 you have when talking about seat moves - and how it relates to skeg/rudder/nothing.
Johnathan has had all three, and knows all about the cockpit moves - but didnāt explain that or make it clear what this means for you in a current production (gen 3) version.
1st gen - cockpit centered at center of kayak (best for rudder - and using fully loaded - as Winters designed it. Probably best trim for speed if used with rudder and loaded as intended (and balancing rudder [size] enhances this, right Johnathan?).
2nd gen - cockpit centered 8" aft of center of kayak (maybe best version for skeg/nothing - worst for racing. Move was intended to meet needs of unloaded day paddling, and largely non-race use, based on customer feedback and use patterns).
3rd gen - cockpit centered 5" aft of center of kayak (3" forward of gen 2. his was also - a customer driven change (by the now clear majority of rudder users and racers among them) that backed off the previous huge move aft and regained a bit of speed/maneuverability over gen 2. OK skeg or rudder - OK day paddling or loaded, or at least better than Gen 2. A trade-off that seems āOKā in a mixed use/user sense).
I moved my seat a full 3" forward - but I have the gen 2 700 thatās cockpit is way back and so I knew I had little to loose and some idea what I would gain. My seat is now exactly where the new ones are - so it wasnāt much of a risk (beyond the damage risk getting that damn thing out). This made it a little tighter to get in/out but let me layback a bit more for rolling and got the thigh braces farther back on my legs - Iām 5ā9". These were the main reasons I moved it. The slight performance/handling gain was a small bonus.
I had a new gen 3 version I donāt know if Iād move it or not - but since itās still 5" aft of the original there may be some room to play and Iād think about it. Iād also think about maybe rigging and adjustable sliding seat -but sort of overkill.