The true answer for you will come when the two cats are introduced to
each other, I may get the same problem. I have a declawed cat, not my
choice, happened before I adopted him at the SPCA. I may get another
cat, but to be fair for the one I have the next must be declawed as
well.

wow.. you will have a pair of amazing cats if this works well.

Have you had a chance to see how your cat reacts to other cats?

Id recommend getting the other cat and keeping separated in a spare room for
a while.  Don't do the introduction for a while.  You'll be able to judge
when by your cat.  If he reacts to the smells in the room badly, it will
take a while.  If he doesn't care, then you'll be able to do the intros
sooner.

Give your resident cat lots of love and praise for all behaviors that aren't
counterproductive to the intro.  do not scold for aggressive behaviors, but
say no strongly and  calmly talk to your kitty and explain why he shouldn't
do that, how you both need to help the new comer feel welcome.  once your
guy shows no aggressive behaviors, switch rooms for a bit.  Let the resident
sniff around the coon's room, smelling everything.  praise him again for all
non aggressive behavior, and once he's done in the room..

so once this all goes well, your ready for introductions.  do it in a
neutral room.. away from areas he considers his. yes.. the whole house is
his, but there are areas that aren't so much so.

It can be done, then again there are times when a kitty just wont get over a
new pet.. but given the right set of introductions you've got a really good
shot.  Good luck.. and don't forget to get the new guy a clean bill of
health before the intro.

Slow and easy is the way to go with adults.  Make sure they are aware of one
another for a while before ever being confronted physically with the other's
presence.  Give the new boy his own room, and let them sniff each other from
under the door.  When you have to clean the new guy's litterbox, bring him
out in a carrier and let the old guy in to smell where the new one has been
living.  Let the new guy explore while the old one is in the room.  Do that
for a week or so, and then bring the new guy out in a carrier and just set
it in the floor and let him get sniffed.  Plenty of love and reassurance for
the old guy, and some Feliway all around and in 2-3 weeks, they'll be
tolerating each other.  They may never bond as "friends", but again, they
might become inseparable. It's all up to the individual personalities
involved.

Sunflower

Yes, ive had this experiance. truthfully, a kitten can tramitize your cats.
but my cats still dont excalty get along. the last cat i got was 6, about 2
years ago. i also had a 2, 1, and 4 year old cat in the house at the same
time. one just hissed and ignored the newbie, and one tryed to attack her,
and the other didnt care at all. all cats have different reactions. they all
get along fairly well now though. good luck!