First understand that home brewing is more of an art than a science. Large breweries deal with amounts that tend to even things out and will even mix batches to hide/dilute batches with “off flavours.”
First, it's a bit too carbonated, bursting from the bottle soon after I popped it.
Gushing is usually caused by two things. To much sugar making it’s way into the bottle, a bacterial infection or both. Autolyzed yeast can also cause this but will be accompanied by really bad off-tastes like say tire rubber.
I suspect too much sugar. Honey can be notoriously slow to ferment the last bit out making it look like fermentation stopped so when bottled that remaining sugar is added to the priming sugar resulting in over conditioned beer.
Note one bottle may not be representative of the batch. Try another after a few days and if it’s also over carbonated then I suggest putting it in the refrigerator to cool it and slow/stop any remaining biological activity.
Due to the carbonation, the dark tan head dissipates quickly.
Weak head can have many causes. Any and I mean any residual soap in anything that touched the beer after the boil will break up the bubble in the final beer (carboy/bottle jet washers are IMO a must). Malt extracts can lose some of the proteins needed for head retention. Also using adjuncts like rice, dextrose, and yes honey lack these proteins from the start. Adding 5% wheat malt to the mash adds extra proteins and chemicals aiding in head retention are also common (even big breweries use them).
The beer itself is nearly opaque.
Most porters sitting in the glass will look dark brown to black. Held up to the light it will likely appear deep red if you can see through it.
The aroma is of toasted grain with a slight tinge of malt.
Sounds perfect.
Flavor is toasty and very dry, suprisingly so.
Honey like dextrose and rice will ferment out completely lending to a dryer/crisper taste. Roasted and black patent malts also give a drier taste. OTOH, if by dryness you mean “mouth feel” its often caused by water with high temporary hardness and or mashing/steeping at to high a temperature.
At first, the bubbles seriously detracted from the flavor -- almost Coke-like carbonation that gave it an acidic edge. That got much better after I let it sit for a few minutes.
Knowing this you an do an aggressive pour to drive out some of the excessive carbonation w/o having to let the beer sit open for to long which will drive off the most volatile aromas. If storing it in the fridge let the bottle warm up to 45-55 degrees for serving for most porters.
Anyone have any opinions on what I to expect after more time?
There are so many variable it’s hard to generalize about much. Generally, beers will mellow with age, a good thing for lagers and some heavy ales but generally a bad thing for lighter ales. Heavier (O.G.) and darker malted (chocolate, roast, black patent) tend to blend with age. Yeast flavors (fruity esters) diminish with age (one reason lagers are “lagered”). The higher the carbonation the more the most volatile aromas/flavors will diminish over time.
If contaminated off-flavors will increase with time especially when stored at room or cellar temperature. The lighter (both O.G. and flavour) the more likely contamination will cause problems.
Cheers (literally),
Dean