Need help on center speaker to match with my front

I just purchased a NAD T753. I have old Linn Index front speakers. Any help/suggestions for a center speaker that will match with the Linn Index in the front?

Thanks in advance,
Buy a used pair of Linn Index speakers. Anything else will be a comprimise. Find two pairs and you will have a perfectly matched 6.1 system.
Thanks for your response!

OK I am new here and I have few problems:
just got my NAD T753 (Linn Index in the front, Linn Afekt sub, Linn Unik center, Denon surround sound) - I know not a perfect setup, but I am in the process of upgrading.
1. Why do we need to buy expensive "full range speakers" when we are going to set the subwoofer to take care of all of the frequency below 60/80 Hz? This is not making sense to me... any help please? I believe a good sub with cheap speakers will do the job as well. What am I doing wrong?
2. The NAD T753 does have the hush noise and it is noticeable... I have also an old (10+ years) NAD 302 integrated amplifier and the sound is much better compared to the T753. Is this the end of the NAD era?
Thanks for you response! So I guess the solution is to use my old NAD 302 integrated amp with my Linn Index speakers for listening to music (NAD 502 cd player), and setup the NAD T753 receiver for home theater using the Linn Afekt sub and 6 low priced/not full range speakers - for example 6 Linn Unik ($225 a piece). It does not make sense to buy good/full range speakers for home theater and then to send all the low frequency to the sub. I think this should be my target - I just need to find 5 more Linn Unik (have one already) and I should be good to go.
I substituted two KEF Reference 104/2 full range speakers for KEF Reference 102/2 monitors. The other speakers are a KEF 100C center channel, and a Velodyne HGS-10 sub, crossing over at 80Hz. I changed the crossover to 50 Hz. As expected, stereo is very enhanced, a larger soundstage with even more precise imaging, and much more LF response. Unexpected, 5.1 has a much greater sense of presence.

I use Proceed pre-amp and digital surrond processor, along with Proceed 2 and 3 channel amps. A Sony 9000ES SACD/DVD and Sony 36 XBR monitor fill out the components. Mostly old stuff, but very good.

I have arranged to purchase a KEF 200C that should better match the 104/2s, and will be adding a second HGS-10. By the way, Auralex SubDude platforms really do result in more bass with less boom.

Bottom line: I'd stick with the old Linns for LR and try to find a Linn that comes close in sound and yet will fit in your center location.

I believe Linn is using KEF drivers, at least in some of their speakers (I think the Linn Index do use KEF drivers as well). So I contacted KEF to see if they will have some recommendations for a center speaker match. For now I will be using Linn Unik for a center, and then I will move it to the back.
Regarding the crossover I am still experimenting - everyone’s recommendations are for 80Hz.