Blaze King Princess Ultra Split Length

The princess firebox is smallest at the bottom. The bricks slope so that as you climb, the firebox will fit larger wood as you climb. Note that the max length spec is for E-W loading, which is a silly way to load a stove and especially the princess so we must assume you intend to load it north south or straight in.

Cut to 16"-17". You can fit 18" in the bottom but it's tight and the last thing you want to be doing is fighting the overlength wood all winter, each winter, until you use it up.

Do you have access to another princess, even at the dealer? If so, then test fit a piece in the clean bottom or even measure it.

I made the newb mistake of cutting to length before my stove arrived.

My encore takes 22 inch logs. Yep it sure does. One large 22 inch split or a few thinly split 22's... Then 2/3 of the firebox is still open and you can't get close to getting another 22 in.

Thankfully I only cut 1 cord this size before the stove arrived. Says 22...Now I cut to 16-18 inches. I know the firebox of my stove is shaped differently than yours....

So my recommendation? Wait for the stove to arrive or cut a few pieces (6-7) and ask the dealer if you can attempt to shove a full load in there.

It is very important or frustration will ensue this next winter.

When I ordered by BK Princess (Ultra versus Parlor etc doesn't matter for this discussion), I saw the 16" spec'd log length and said "this is silly, I'll just load the logs sideways" (as I had a bunch of 18-20" logs).

After experimenting with the straight-in placement I realized that you can get WAY more wood into the stove that way, plus (this may be my imagination) it burns better. So now I religiously cut my wood to 16" lengths and recommend you do the same.

Not sure of the free stander is the same as the insert but the box is square, I know the insert's box is a tad smaller at 2.54 compared to 2.85/ but 16 inch works well for both units.
First year I got all my wood before I knew what stove I was going to buy and my wood was all 2 inches too long, what a pain to trim down the splits, I ended up making a box so I could do several splits at a time but still something best avoided. You can't go wrong with 16 inch and you're going to get such a long burn time it won't matter, I get long burn times when I fill my box up with odds and ends pieces.

Using the default standard length of 16" has other benefits too. You can sell or give away your extra. You can stack three rows on a typical 4 foot square pallet.

16" split length...you and your F-I-L will both be happy burners.

Highbeam nailed it with his first post. You can fit about 17 1/2 max on the bottom or first row loading n/s. After you're above the bricks you can easily fit 18"+. I shoot for 17 but a little less or more is fine with me. If I miss long I just toss them on the second layer in the stove.