What battery did you start with in the plane? If you want a drop in replacement with zero effort, I have never found a substitute for the RG-25, for instance, that's what my box was built to hold well.
As others have said, the PC925 is going to be what I'd put in a RV-10. The terminals are available either side Positive, so get the one that suits the RG 25 replacement. The bolts will best match the RG-25. In the PC925L, left is positive if the label faces you, this puts the battery when rotated a near- match for the RC-25. The terminals will be on the vertical edges rather than on the top of the RG25. The PC925L is only 6.5 inches wide where the RG is 7.7 in this layout. Height is 6.97 for the PC925L vs 6.81 for the RG-25 and depth is 4.93 inches for the PC925 vs 4.97 for the RG-25.
If you can afford the time, pull the battery, top it off with a charger, if not the "right" one, don't leave it overnight, let it go no higher than 14.5 volts. Load test it. I use a 500w inverter and a few 100w box fans. Should go 45 minutes before hitting the low voltage cutoff of most inverters. If the battery is good, check and clean as many connections, including grounds, as you can.
No need to go cheap, but here's my $ saver that fit my battery box much easier-
If you want a sport AGM- the cheapest easy swap...
A RG-25 XC near drop-in replacement exists- however- Concorde does a nice job of keeping the bolt connections recessed from the top and set back from the edge. This matters little if you use a strap type top retention with sides and front walls well short of the top. It is more a concern for a true battery box enclosure.
Most all AGM sport batteries but the Oddesey line scare me a bit. The connections are high and at the edges/corners. Oddesey is a pricey brand, but great value and the 925 has the same endurance AH as the Concorde easily. That said-
I like the made in the USA and sold under many labels Deka ETX-30L $120, or so. Check if you have a local dealer, that worked great for me. East Penn I believe is the parent for Deka and Duracell Ultra brands. The Batteries and Bulbs Duracell Ultra for big Harleys with grey case is the same as the Deka and the $130 price is fine.
CYL10020
Brand: Duracell Ultra
Voltage: 12
Format: 30LA
Lead Acid Type: Starting
15 minutes jigsawing and sanding a few 3/8" thick mdf shapes and all set in an aluminum box that held the RG-25XC previously between the rudders of a RV-6.
Don't forget to make sure you have snug fit and no chance of a short in all 3 dimensions. Folks have wound up upside down with a battery shorted hot to the box.
I'd try a LiFePO4 in a blink if I had a battery mount on the firewall-forward side and an over-voltage protection device. If you don't need the reserve of the Concorde you could have a 4# battery. I think the RV-10 is a cabin battery, so you'd need a sealed installation with venting and enough reserve for IFR AH needs.