I want to use a t-molding between a nailed down hardwood floor and a floating laminate. The leg on the t-molding I have is shorter than the distance to the subfloor. So, I'm looking for some advice. Here's the options I thought of.

One was using a thick bead of construction adhesive to fill the gap to the subfloor, but I am worried that that will leak out to the side and fill the expansion space for the laminate. What would be the maximum gap between the bottom of t-molding and the subfloor to just go with this approach?

Second option was to shim it. That sounds simple, but again I am wondering with the shim what distance I should aim for. Should I have the leg touching the subfloor, or else make a small gap I could fill with construction adhesive?

Third option was to ignore it and not fill the gap. If I have the t-molding secured to the hardwood floor with construction adhesive on both the horizontal and vertical sides of the hardwood (i.e., the bottom of one side of the t-molding and one side of the leg), and there is a gap between the leg of the t-molding to the subfloor, will that be ok? If both sides of the t molding rest on flooring would that be strong enough?

There is a minor height difference between the hardwood and laminate. The hardwood is about 1/16" higher. I thought about shimming that or slightly tilting the t-molding.

Thanks for your help.

Hopefully your using a solid wood T-mold, the legs are often different depths. You could just fire a few long finish nails threw it since your on wood.
If I shim you must check the space with a small piece to see the space that needs to be filled, not to tight as to allow adhesive under both pieces.
Or as a last resort you could adhere it to the solid wood edge, leaving ample space for expansion.
Laminate T-molds can be smaller in dimension.

Yes, it's a solid wood T-molding. So, you're saying that if I use construction adhesive on the edge of the hardwood flooring, and put a couple finish nails through the T-molding into the hardwood too, then I don't need to worry about there being a gap between the leg of the T-molding and the subfloor? If I understand you right, that's great, thanks.

Not into the hardwood, it needs to move and should move less than the laminate depending on species.

I also staple or pin a thin strip of desired length to the bottom of the leg and glue with a couple pinners to hold in place or weight down.

Remove 1/16" from the bottom of the side that sits on the hardwood. Cut a piece of wood the same width as the leg and long enough to fill the gap so that the leg now reaches the sub floor. Glue this extension piece to the bottom of the T. Safest way to attach T molding is to predrill through the center of the T molding so the nail goes through the T. Cut the head off a finish nail and use it to predrill through the T. Use the same size finish nail to nail the T molding. You can use a nail gun but be extremely careful near the ends of the T molding.