Two parts here, and I hope I come across helpful, sometimes correcting statements comes across wrong
So, first part, I think you are falling into the DCR trap that makes people distrust it. I actually like it, but it requires a couple of important things. 1 - accurate measurements and 2 - a common tool that has been used on more than one build to have a reference.
Not knowing your exact chamber size (they vary, sometimes wildly) , deck clearance, and what seems to be an assumption on the pistons means that DCR is already unusable. Second, that Wallace calculator is not one that most everyone uses. I can't speak for everyone on here, but I can reach out and say most that have experience with comparisons use the PKelly program, which you can download. The reason using the same one is important is that who knows what the correct number is? but after 4-5 or 20 builds, if a range using one calculator seems to work, then you can trust THAT calculator for THAT range
So, to the engine. I did do a WAG DCR just to see then went to the wallace calculator. Assuming .030 over 14 cc piston, .010 below, 74 cc chamber, .041 gasket with 4.4 bore, and that cam actually with a 57 degree IVC,
PKelley's program says 9.82:1 compression, 8.30 DCR
Wallaces program says lower 8.1 but it's based on static which I had to guess
So you can see that the number is really useless. Bottom line, I think that combo, is OK, if your numbers are clsoe to the common guesses I just assumed
So, run on.
Here is what I think
1 - Not the carb itself, but possibly adjustment
2 - Timing
3 - Heat
4 - Idle speed
So first, take a good look at your timing. A good start is 12 initial, but then you need to look at the total to make sure you don't have too much, I'd shoot for 36 total and likely in by 2800. Good easy rule of thumb
Second, with more initial, you can close the carb, an engine cannot diesel without air, fuel and heat. Your carb was likely open too far allowing it to get air and some fuel.
Third, if it's a fresh motor, it'll make some heat for a bit, if there is any way to put fans up, go for a ride, you name it, let it break in. You can also consider long term putting a colder thermostat in it, but at this point I think it's more carb and timing related.
Fourth, idle it as low as you can. That little cam should idle nice and low, under 700 IMHO. As you troubleshoot, if you can't idle it lower, shut it off in gear, but don't let it sit there and chug, that's pretty tough on the reciprocating parts
I'll also ad, better go back and check your work, loose carb bolts...what else is loose? We all make mistakes, I wish I had a dollar for every mess up but once you find something like that, give it a good once over, reset the timing, etc.
In the end though, I don't think you have a compression problem and you should not need a bigger carb just a properly adjusted one