So many choices, very vague idea what should be done here.

Very tough position. Let me blunder.

We have a huge race lead, so priming is a distant plan, especially with that blot on the ace.

We might think about building though, since if White goes into hit exchange, we might use the stronger board for pushing him into gammon danger. We might also use that ace point blot for this plan by covering it, which strengthens our blitzing potential.

For racing I'd consider 13/10 21/18(3).

13/10(3) 21/18 might look OK at first glance but I don't think it is. It disconnects our rear guys, and bring builders to build, when there will be no building next roll, because most likely we will be on the bar after he hits on 18pt. with most rolls.

For building I'd consider a bold 8/5(2) 6/3(2).

Something inbetween like 8/5(3) 13/10 might be OK, too.
Such balanced play are strong contenders when other plays that focuses mainly on a single goal doesn't look that great.

Talking about balanced plays, I think 21/18(2) 8/5(2) and 21/18(2) 13/10(2) are also worth considering. The first one dupes White's 6s and 4s.

With so many choices my head starts spinning, and I drift into the blunder zone, because all plays have some merits, but only few can be good. Nevertheless I think I'd choose one of these balanced plays.

21/18(2) 8/5(2) and 21/18(2) 13/10(2) feels too blotty for such race lead - reject.
On a side note, quick glance at the racing 21/18(3) 13/10 again and it just doesn't improve enough - reject.
That leaves 8/5(3) 13/10.

8/5(3) 13/10 for me.

What about 13/1*? It doesn't look impressive, but it delays white, covers your blot, and lets you see the next roll before committing to a plan.

would really be surprised if 13*1 is any good, we're way ahead as it is and need more structure

I'd just unstack the 6pt - 6/3(2) 21/18(2)

Yeah, that's XG's recommendation.

That is what I actually did. At least it covers the 1pt, but with a wrong checker, as I think about it now.

Here's how I would think about this:

You're up 17 in the race and you just threw 3-3, so you'll be up 29 after you play. That's a big racing lead and it needs to dominate your thinking right now. Your primary goal is to disengage to the extent you can, so let's start with 21/18(2), advancing the back men to a better anchor. You'd like to move the last checker from the 21 to the 18, but it leaves you with no good final 3, so leave him back on the 21. At least he's now a checker that's free to move without breaking a point.

For the last two 3s, just play 6/3(2), which unstacks and makes an inner point. You have to fill in your board sometime and the order of points doesn't matter much anymore since White isn't going anywhere.

The result is a pretty good position: spares on the 13, 8, and 6, plus a checker to move back on the 21-point.

You have to reject 13/4*/1 almost immediately. You make the 1-point, White enters, and now what? All you've done is waste what should be a really great roll, killing another checker in the process.

Grunching. Seems like 3(2) and 18(2) to me. 6 point is crying to be developed and you're ahead in the race, so getting a more advanced anchor while keeping a back spare to play with seems more useful than alternatives like 10(3) and 18, which really disconnects you.

As for my playing style, in this beginning stage I forget everything what I have learnt. I would play 8/5(2) and 6/3(2). 21/18(2) is also okay for me, but don't try at home. As an excuse in this particular position, I can argue that the 1-point is out of play, and that some future bar missions would be welcome.